Famciom vs. AV Famicom External - Internal Audio Mixing

There is a myth that the AV Famicom is too quiet when it mixes internal audio with external audio.  The myth goes that the external cartridge audio drowns out the internal audio from the console and gives an unbalanced and unfair impression of what the programmer intended the music and sound effects to sound like.  The conclusion is that an original Famicom, preferably an earlier model, is the ideal way to experience Famicom audio.  However, this conclusion is too simplistic and the internal/external mix is not as extreme on standard Nintendo Famicoms and AV Famicoms as one may be led to believe.

Of course Famicom audio has its own problems.  The first problem is that genuine Famicom audio is encoded into RF and decoded in a TV.  The baseline audio has a buzz and the output of the audio sounds like it was run through an oppressive low-pass filter.  The second problem is that playing a Famicom with its RF video and hardwired controllers is something of a chore.

I have made some recordings of several games which use Famicom expansion audio and internal Famicom audio.  The games in question are :

Zelda no Densetsu (Famicom Disk System, The Legend of Zelda)
Akumajou Densetsu (Konami VRC6, Castlevania III: Dracula's Curse)

Famicom and NES Expansions and Peripherals

Famicom Peripheral List

Devices that Plug into the Famicom Cartridge Slot

Nintendo Famicom Disk System

• 199 Official Licensed Games + Prize Cards (and unlicensed games, copying programs etc.)
• Comes with a disk drive and a RAM Expansion.

The RAM Expansion is inserted into the cartridge slot and the cable from the RAM Expansion is connected to the rear of the disk drive.

Famicom Homebrew : So Close, Yet So Far

NES homebrew has been around for a very, very long time.  Chris Covell's Solar Wars, which is the first complete NES game developed independently, came out in October, 1999.  This was a mere four years after the NES was officially discontinued in 1995.  In those days, the Nesticle was the emulator of choice for playing NES games, but was very inaccurate at emulating the hardware.  Nonetheless, Solar Wars established an important precedent by working on real Nintendo hardware.

Unfortunately, if you wanted to play Solar Wars back in 1999, you had to modify an existing NES cartridge. Fortunately it uses a common PCB, but not everyone had access to an EPROM programmer and soldering and desoldering tools.  The next step was the release of the first homebrew cartridge the Garage Cart, was released by Joey Parsell (Memblers) in 2005.  It cost $42.00 and included Solar Wars and two other small games.  While it still used a donor board, it was significant in that you could purchase one and play it on your real NES without any programming or soldering hassles.  

Analog Controllers in Consoles and Computers

A digital joystick is just four contact switches activated by pressing a directional instead of a button.  This includes the Intellivision's controller, which has sixteen discrete positions, and most console "joysticks".  An analog control allows for smoother movement instead of relying solely on the amount of time a directional has been pressed.  Originally, analog knobs or paddles were used with Pong and other ball and paddle games. Eventually the combination of two of these "paddles" with a common control became a joystick and achieved some popularity for racing and flight simulators.  Outside these pigeonholes, most of the popular games of the 70s and 80s used digital joysticks, trackballs and rotary spinners (the latter are used in the Breakout-derived Arkanoid).  Only in the mid-90s with the rise of first and third person 3D games did a compelling need for a general analog controller present itself.  In the blog post, I will discuss how analog controllers used to be used and how they are used today.

True analog controllers in the video game world use variable resistors.  The humble variable resistor, also called a potentiometer, has had a wide variety of applications.  You will see them at work in light switches, to change volume or temperature.  They were often used in video game controllers.

There are two ways in which analog control was implemented at the hardware level, and both involve potentiometers.  The most common way is to use the potentiometer as a variable resistor in a resistor/capacitor discharge network.  In this method, a capacitor is discharged then a port is read until the capacitor indicated it was recharged.  The time it took for the capacitor to charge gave the position of the potentiometer.  More resistance equals a longer charging time.  Only two wires are connected to the potentiometer in this case, one of the end terminals (to +5v) and the middle terminal is connected to the console.

The second method is to use the potentiometer as a voltage divider with a comparator.  In this method, the potentiometer's output voltage is compared to a voltage ramp, which is reset, and the time it takes for the voltages to become equal indicates the stick's position.  In this case, all three terminals of the potentiometer, one end to +5v, one end to GND and the middle terminal gives the signal to the console or computer.

Atari 2600 & 7800

The Atari 2600 usually came with a pair of paddle controllers.  Each paddle had a potentiometer connected to two terminals, making it function like a variable resistor.  Each controller port could support a pair of paddles but only one of any other type of controller.  Paddle games were the only official solution for four-player gaming.  The output line of these potentiometers is connected to the TIA chip.  The rating of these potentiometers is 1MOhm.  Each paddle had a single button, which shared the same line as the left or right joystick directional.  Button inputs are connected to the 6532 RIOT chip.

Interestingly, while not an analog controller the Keypad Controllers and their clones also make use of the potentiometer lines.  There are insufficient digital inputs on the 2600 controller port to read a 4x3 matrix.  What the 2600 does is to set the joystick inputs as outputs and send a signal through each of the four lines.  These correspond to each horizontal row of keypad keys.  One column is read via the joystick fire button input on the TIA and the other two columns are read through one of the paddle input lines with the assistance of a 4.7KOhm resistor.

The Atari 7800 is backwards compatible with the Atari 2600 and includes a TIA and 6532, but no 7800 games support analog controllers.

Apple II

The Apple II and II+ came with a 16-pin socket which could accept four paddle inputs.  These systems came with a pair of paddles with the Apple logo branded on them.  Like the Atari paddles, these operate as variable resistors.  They use 150KOhm potentiometers.   Soon someone figured out that you can pair two paddle inputs to make a joystick input.  Unfortunately, there were only three button inputs, making the use of two joysticks rare.  Typically a single joystick would only use the first two button inputs.

The Apple IIe kept the joystick socket but also added an external DE-9 port containing the lines necessary to support the four analog inputs and three digital inputs.  This port uses the same lines at the 16-pin socket, but it is easier to plug in and remove peripherals from the external port than the internal socket.  The Apple IIc removed the internal socket and required the joystick to share the port with a mouse, limiting the joystick to two analog and digital inputs.  For the IIe and IIc Apple released a joystick and paddles separately that use the DE-9 connector.  The Apple IIgs has the capabilities and connectors of the IIe but also supports a fourth digital input for four buttons.

Tandy Color Computer, IBM PC & Tandy 1000

The IBM PC uses a DA-15 gameport supporting four axes and four buttons.  The Tandy Color Computer and 1000 uses a pair of DIN-6 connectors, each supporting two axes and two buttons.  All of these computers use 100KOhm potentiometers, but the IBM standard wires them as variable resistors and the Tandy machines wire them as voltage dividers.  Like the Apple II, these interfaces use discrete circuitry instead of a custom chip.

Tandy's regular CoCo joystick uses one button and are non-self centering.  They are not regarded highly.  The Tandy Deluxe Joystick is self-centering, has two buttons and can be set to free-floating mode.  The IBM PCjr. joystick has the same features and look identical to the Tandy Deluxe Joystick, but has a different connector and is wired as a variable resistor.  Both joysticks hail from Kraft-designed joysticks, which were pretty much the standard for the early to mid 80s for the Apple II and IBM/Tandy.

See here for more discussion of issues relating to the IBM PC joystick : http://nerdlypleasures.blogspot.com/2014/03/wheres-my-digital-joystick.html

The Apple II usually runs at one speed and unless an accelerator is being used, the constant speed eliminates issues with reading from the joystick port.

Commodore VIC-20 & Commodore 64

The VIC-20 has one joystick port, so only one pair of paddles is supported.  The paddles are connected to the 6560 VIC chip, which provides video and audio.  Because the paddles are wired to the Atari standard, the buttons are handled by one of the 6522 VIA chips.

The C64 has two joystick ports, so two pairs of paddles are supported.  The paddles are connected to the 6581 SID chip, which also handles the audio for the computer.  The SID chip only has two analog potentiometer inputs, so the inputs from two pairs of paddles are multiplexed and read with the assistance of one of the 6526 CIA chips.  The CIA chip also handles button reading.

Commodore's paddles can be used with either system and they use a resistance value of 470KOhms.  Atari 2600 paddles are more common and usually work OK, indicating that Commodore's paddles are wired as variable resistors.

Atari 8-bit Computers and 5200

The Atari 400 and 800 computers could support four pairs of paddles using its four controller ports.  These are connected to the POKEY chip inside the system, which has eight analog input pins.   Super Breakout for the Atari 8-bit computers supports eight paddles used in a sequential fashion.  POKEY is also used for audio generation and other system functions including scanning the keyboard for pressed keys. The buttons are read by the 6520 PIA chip.  The 2600 paddles are used in these computers.

The Atari 5200 was noted for being the first system to come with an analog joystick.  The Atari 5200's joysticks manipulates a pair of potentiometers (not smaller than those found in paddles) and use a resistance value of 500KOhms.  The 4-port system could, as its name implies, support for of these joysticks.  The 2-port system could only support two joysticks.  No paddles were specifically made for the 5200.  There is no PIA chip in the 5200, so the joystick buttons are read by the GTIA chip.  The keypad buttons are read similarly to the keyboard keys in the 8-bit machines by the POKEY, but multiplexers are used.

The later Atari 8-bit machines, from the 1200XL, 600XL, 800XL, 65XE, 130XE and XE Game System eliminate two of the controller ports, so you can only use two pairs of paddles with these machines.

Vectrex

The Vectrex controller may not have had quite as many buttons as the 5200 controller, but four independent fire buttons was a rarity.  Its joystick was smaller than the 5200's and apparently less brittle.  Also, far more importantly, the joystick is self-centering.  The innards of the joystick look very similar to those of the Sony Dual Shocks to come in the following decade.

Not only does the Vectrex controllers contain a pair of potentiometers attached directly to the joystick, but there are also a separate pair of trimmer potentiometers located elsewhere on the PCB.  Apparently these can be adjusted without opening the joystick and serve to fine tune the joystick's centering, not too dissimilar to how Apple and PC joysticks work.  These trimmer potentimeters are 10KOhms.

Unlike the Tandy sticks, which have one end terminal of the potentiometer connected to +5v and the other end terminal connected to GND, the Vectrex stick has one end terminal connected to +5v and the other end terminal connected to -5v.  The resistance value for these potentiometers also appears to be 10KOhms.

Because Vectrex controllers are rare and only two commercial Vectex games use the analog function, Sega Genesis 3-button controllers have been converted to work with them.

NES & Famicom

NES Controllers are primarily digital, they send out a bit for a pressed button.  However, the NES and Famicom versions of Arkanoid were released with a paddle controller.  This controller, called the VAUS Controller in the US, could be used instead of the gamepad.  The Famicom controller plugged into the expansion port and the NES controller plugged into Controller Port 2.  The paddle had one button.  The NES and Famicom controllers are not compatible with each other, they function identically but use different bits to send their data.  No other NES game used its Arkanoid controller, but the Famicom games Chase HQ and Arkanoid 2 could use the Famicom Arkanoid controller.  The NES controller has a small screw that could be used to adjust the sensitivity of the controller via a trimpot.  The Famicom controller does not have a trimpot.

The interior of the Arkanoid controller shows a 556 timer and potentiometer wired only to two terminals.  This means that it works just like in the Apple II or IBM PC.

Thumbsticks - Sony PlayStation Dual Shock controllers and their successors

Outside the classic consoles, most systems of the third and fourth generation of video games did not support analog controllers.  In the fifth generation, things began to change.  The Nintendo 64 was released with an "analog" thumbstick, but the thumbstick uses optical sensors and is not really an analog controller for the purposes of this article.

The basic principle of how the analog thumbsticks operate on a PlayStation Dual Shock controller is similar to how the Tandy CoCo joysticks work.  Although its successors may offer more analog controls, the basic functionality is unchanged.  Essentially each thumbstick manipulates a pair of potentiomers, one for each axis of the stick.  These potentiometers are wired in the three pin style, making them voltage dividers.  When the stick is in the neutral position, the sticks should be outputting half the maximum voltage (2.5V).  The controller chip of the controller reads these values and converts them into a digital 8-bit value which is sent with other stick and button information as a multi-byte serial packet to the console.

I have read that using a voltage divider is more precise than using a resistor/capacitor network as used in PCs and Atari consoles and computers.  However, potentiometers are notoriously loose with their tolerances (20% seems to be the norm).  I imagine Sony and its competitors may have higher quality parts and the lower resistance ranges (0-40KOhms seems to be about right) and the shorter travel distances may tighten the tolerance a bit (10% seems reasonable)

Every PlayStation game that supports the thumbsticks should use a standard routine to calibrate the thumbsticks when the game is bootup.  Even with tighter tolerances and more compact form factors, the dead center position may not reflect the midpoint voltage reading.

Will the Real Successor to the Pitfall Legacy on the NES Stand Up?

There never was a game called Pitfall III.  David Crane programmed the original Pitfall for the Atari 2600 in 1982 while working for Activision, a company he co-founded.  Two years later he released Pitfall II: Lost Caverns for the Atari 2600.  Thereafter came the great Video Game Crash and Crane left Activision in 1986 to co-found Absolute Entertainment.  While there would be other games in the Pitfall series, this blog entry will discuss three games released or were to be released during the third generation of home video game consoles would could compete for the right to be called the successor to the Pitfall Legacy.

In the Beginning: Pitfall and Pitfall II: Lost Caverns

Pitfall essentially made David Crane as close to a household name as video games got before the Crash and cemented his reputation as a game designer worthy to be inducted into The Academy of Interactive Arts & Sciences' Hall of Fame.  This game was a massive success in its day, selling over four million copies and ported over to all the major consoles and many of the popular home computing platforms of the day.

Starting Screen with Stationary Log

Pitfall is one of the first platforming and side-scrolling games, even though the Atari 2600 hardware did not accommodate scrolling and this game only used static screens.  This game was inspired by Raiders of the Lost Ark and invited players to explore a large, non-randomized world.  In fact, Pitfall is actually far more popular than the official 2600 Raiders adaptation because Crane was able to pare the exploration concept to the basics while still maintaining a sense of fun.  You can just pick up and play Pitfall, Raiders requires reading the manual and a lot of trial and error in order to make any sense out of it.

Swinging over a crocodile lake

There are many dangers in Pitfall : tar pits, lakes (both of which can expand and retract from what appears to be solid ground), crocodiles, scorpions, snakes and campfires that can kill your character, Pitfall Harry.  Logs can steal points if you collide with them, vines can allow you to cross over dangers, you can jump on the crocodile's heads to get over water, ladders and holes allow you to go underground and the underground passages allow you to "warp" a few screens, if there is no brick wall in the way to block you.  Multi-colored "sprites", a relatively detailed background and catchy sound effects and jingles make the game a visual and aural treat for the 2600.

Swinging over a tar pit and rolling logs

Finally, there is plenty of challenge in that you have to locate 20 treasures strewn across 256 screens in 20 minutes with 3 lives.  You will need to map and plan carefully and identify useful warp passages if you want a good chance of finishing the game.  Important to note that unlike most other Atari 2600 games this game will end (it just stops) if you find the twentieth treasure.

Camping out

One other important theme to note here is that Pitfall Harry has no way to kill any of the enemies which he encounters.  In Pitfall, you have to jump over or otherwise avoid all obstacles, including animals.  This aspect will be maintained in the other games Crane designed and discussed in this article.  Ultimately finding non-violent solutions is a recurrent theme throughout almost all the games Crane has designed.

I forgot to bring my tambourine

Two years after Pitfall, Crane released his sequel, Pitfall II: Lost Caverns.  He did not reinvent the wheel or take the series into a radical new direction.  Some sprites and mechanics were taken from the previous game and the two games are visually similar.  However, he expanded the concept by taking the basic exploration theme of the original game (which only used the horizontal plane) and expanded it into the vertical plane.  There are eight horizontal screens and twenty-seven vertical depth levels which you can explore.  In other words instead of having 255 screens stacked together horizontally, you have a grid of 8x~8 screens, adding an extra dimension to the world.

Starting Screen with Checkpoint and Eventual Goal

Now Pitfall Harry can swim in water and has checkpoints to start at if he is "killed". You do not die in this game, you just get sent back to the last checkpoint.  Nor is there a time limit.  There are several new enemies, like electric eels, frogs, vultures, bats, the rat and the return of the scorpions.  The  vultures and bats travel in a repeating pattern across the screen.  In addition, each time you enter the screen they may start from a different position than the previous time you entered the screen.  This makes it hard judge when you can run underneath them, but you have to run past them to make progress in many areas.  At one point you will need to catch a balloon to progress further in the game.  

Bat and Rat

You can find typical gold brick treasures for points, but the object of the game is to find your pet Quickclaw, your girlfriend Rhonda and a diamond ring.  The game ends when you obtain all three with Harry doing some victory jumps before the game stops.  You loose points by colliding with enemies or falling and landing after a certain height.  The screen scrolls vertically as you descend and explore the "lost caverns".  The look of the game is still very much in line with Pitfall, and like Pitfall, the only thing you can do is climb and descend ladders, walk left and right or jump.

Scorpion, Swimming and Treasure

Crane designed a special hardware chip for the cartridge called the DPC.  Because of this chip, Pitfall II was undoubtedly the most complex cartridge ever to be released on the Atari 2600 during its lifetime.  The DPC chip allows bankswitching up to 10KB of ROM (Atari carts are only 2K or 4K without bankswitching; Pitfall is a 4K game), a hardware random number generator, hardware to assist with graphics processing and hardware to generate the data to feed into the internal 2600 audio to create three additional channels of sound.  There was not enough space to put the Adventurer's Edition second quest into the 2600 original that was present in the Atari 5200, 8-bit and Commodore 64 versions of the game.

Watertfall and Electric Eel

Frogs, Ladders and Multiple Levels

Thanks to the DPC chip, Pitfall 2 has music playing throughout.  There are four pieces of music, the treasure theme, the return to checkpoint theme, the default theme and the balloon theme.  This music plays according to what happens during the game.  Multi-channel music as heard in Pitfall 2 is difficult to pull off on the 2600, but when coupled with an advanced game engine like Pitfall 2's, it needed hardware assistance.

Multi-level Madness

Vultures

A Boy and his Blob

Title Screen

Start Screen

The 2600 was too long in the tooth when David Crane was developing A Boy and his Blob, the 7800 and the Sega Master System did not have the market share and the Commodore 64 was dying in the US.  Having left Activision, he had no more right to create a Pitfall sequel than I would.  He ended up creating A Boy and his Blob for the dominant platform of the day, the NES.  A Boy and His Blob to me feels like Pitfall III and in addition to having its creator at the helm, let me explain the design similarities between this game and its Pitfall predecessors.

No money, no healthy food

A subtle way to inject the production team into the game

The Boy in the title is less capable than Pitfall Harry, he can only move/run left and right, he cannot jump unaided.  However, he has a companion, the Blob, which functions as a puzzle solving device.  Using different flavored jelly beans, the Blob can do different things.  Need a ladder, feed him the licorice jelly bean.  Want to drop down to the next level, turn the Blob into a hole with the punch jelly bean (you can do this multiple times for one bean).  While you have 15 flavors to choose from, your supply of jelly beans is limited and you need to use them wisely.  The Blob and jelly bean mechanic represents an evolution over using the character's own abilities to get past obstacles.

Treasure and Subway Serpent

Don't try this in real life

Like Pitfall 2, this game requires exploration of caverns beneath the surface.  Similarly, the game is structured in a grid of non-scrolling horizontal screens.  Unlike Pitfall 2, the screens do not scroll vertically, despite the superior NES hardware.  I do not believe this was done because David Crane could not figure out NES scrolling but because the levels were so vast and less structured than Pitfall 2 that it would have made map making much more difficult.

Cinnamon & Spice

The caverns have many dangers, including subway serpents, falling rocks, spider webs and stalactites and stalagmites in the water.  However, unlike Pitfall 2, the omnipresent danger is death by falling.  If you fall more than one and a half screens (without a device that can ease your fall), you die.  You start off with five lives in this game and no continues.  Also, your Boy moves a lot looser than Pitfall Harry, so you may run into something you cannot avoid and cannot turn back quickly enough to lose a life.  You cannot swim but the Blob can help you with that.  Finally, if you lose a life you will start at the point where you found your last treasure similar to Pitfall 2's checkpoints.

That Blob is very strong

But running under those subway serpents is still tricky

Mind your height

The goal of the first half of the game is to find treasures and escape the caverns.  There are 22 treasures located in different areas of the underground caverns, similar to Pitfall 2.  At the bottom of the caverns you will find an underground lake just like in Pitfall 2.  These treasures allow you to buy vitamins that you will need on the Blob's home planet, Blobolonia.  The second half of the game is a shorter experience where you have to dodge more enemies and defeat the evil, sweets-loving emperor.  Ultimately, gameplay is the key focus of this game.  The graphics are drab and backgrounds are mostly black underneath the subway.  It is quite easy to get lost because screens often look alike.  Music is limited to one basic piece of music for the game (in addition to the title screen music) and a few sound effects and ditties that play at certain times.

You will need to do this very often

Super Pitfall

Title Screen

I am aware that there is a game for the NES called Super Pitfall, but that is an abomination that David Crane had nothing to do with.  It is a port of a Japanese PC-8801 game by Pony Canon where is was called Super Pit Fall. Post-founders-era Activision licensed the title and published it as one of its first NES games. Activision may hold the rights to the Pitfall brand, but that does not mean it earns a place here considering its pedigree.

Spider and Bat Enemies and Water

Super Pitfall is a stripped down port from programmers who did not quite get the NES.  Scrolling is choppy, graphics are barely NES-worthy, the music is a 15-second piece intended to give you an idea of what hell feels like and there is quite a pause as the level loads.  You can now duck and shoot a gun with limited ammo and there are a couple of bosses, which pretty much sums up the evolution of this game over Pitfall 2.  Hit detection is unfair.  Even the manual states that the gun will feel useless at times, which is refreshingly honest. You can see glitches with sprites not infrequently.  The gun mechanic does introduce an element foreign to Crane's Pitfall games.  Also, items are invisible, so you have to jump in certain places to make them appear.  The game is filled with cheap deaths, in fact if you go down the first ladder in the game you will almost certainly die.

Bats and Frogs

Like Pitfall 2, you have to obtain the diamond, the pet and the girlfriend to win the game, but there are more obstacles to overcome. The world is huge (270+ screens) but you only have three lives and no continues, so it will be difficult to get a feel for it.

Waterfalls, Spikes and Treasure

Super Pitfall 2

Title Screen

There was going to be a game called Super Pitfall 2 released for the NES, but was canceled.  There is a prototype ROM floating about.  Super Pitfall 2 was a port of another Japanese game, this one a Famicom game called Atlantis no Nazo (Mystery of Atlantis) by Sunsoft.  The prototype appears to differ from the Japanese original only in its title screen.

1st Zone

Unlike Super Pitfall, Super Pitfall 2 is competently programmed.  Sunsoft was willing to hire competent programmers, Pony not so much.  The graphics are still bland but the music is pretty decent and the control is not quite as frustrating.  Your weapon is a bomb that you can throw, but it detonates when it wants to and can kill you if you are in its (short) blast radius.  The jumping could use more polish (you cannot change your trajectory in mid jump like Castlevania) and the game will get frustrating very quickly.  The bats dropping guano as a weapon is a nice touch.  The shell crabs will hide in their shells if they perceive a bomb coming, so killing them is a bit tricky.  Still, the violent solution is out of place in Crane's Pitfall games.  

2nd Zone

Ultimately, Super Pitfall 2 is really a horizontal side scroller.  The level progression is fairly linear and it does not feel like a Pitfall game at all.  You can find doors that will take you to a small portion of a later zone, but the game is still linear.  Even Super Pitfall was better at conveying an open world.  Pitfall's influence on the game is still present.  The enemies appear to be mostly of the natural variety and there are treasure chests you can open for points.  Between its lack of a real Pitfall feel and its rather long-in-the-tooth status for 1989 when Activision was considering porting it, it is no surprise that it eventually went unreleased.  An optimist may wish to believe that Activision saw that its former founder had released a Pitfall-like game in the same year and did not want to compete with him, but my idea is probably the more likely reason.

3rd Zone

Famicom Expansion Audio Carts - Best Examples

During the Famicom's lifespan, 26 cartridge games were known to support expansion audio.  The Famicom directed its audio to cartridge port and games that did not use expansion audio would simply loop it back to the RF modulator.  The expansion audio that these 26 games would generate would intercept the internal audio and mix it with the expansion audio and send the combined signal to the RF modulator.  In addition, 75 Famicom Disk System games (4 of them unlicensed) are also known to use expansion audio generated in the FDS RAM Adapter.

Here is a list of all Famicom games known to use Expansion Audio : http://wiki.nesdev.com/w/index.php/List_of_games_with_expansion_audio

In this post, I identify the most accessible games for English speakers using each expansion audio chip and describe what needs to be done to play it.

Sunsoft 5B

Gimmick! - The original cart alone can go for $200 easily, however, there is at least one other more common Famicom cart (Gremlins 2) with a Sunsoft 5B chip, but obtaining one is something of the luck of the draw.  Additionally, one can make a donor NES cart with a Batman Return of the Joker and an AY-3-891x chip, or you can get a INL-ROM NES reproduction board with an AY chip on it.

Konami VRC-VII

Lagrange Point - This is the only game that uses the expansion sound capabilities found in this chip, which is exclusive to this game and Tiny Toons 2 Japanese version.  Tiny Toons 2 does not have an SRAM chip, battery or any of the passive components to mix the audio, so it would be a large undertaking to get it to work in a NES cart.  I am not sure whether the Largange Point board plus a pin converter would fit inside a NES cartridge shell because the game's board is very tall.  You may need an external pin converter.  Interest in this game has also increased substantially because of a full translation patch.

Nintendo MMC5

Just Breed - This is a large strategy RGB from Enix and one of the three games that use the expansion audio of the MMC5.  Because of its translation patch, it is by far the most accessible of those games.  The original cartridge can have its ROM replaced with a translated ROM burned onto an EPROM, some minor reworking will be required.  Because it uses Nintendo's MMC5 board, this can work with a reproduction cart in a NES.  The most suitable NES cart is Gemfire, but I suspect that any of the battery backed MMC5 boards will work with some minor reworking. Castlevania III and Laser Invasion will require the addition of an SRAM chip and a battery, not a beginner mod.

Konami VRC-VI

Akumajou Densetsu - This is the Japanese version of Castlevania III, and does not have so much Japanese text that it requires a ROM swap to enjoy it.  The Famicom board is small enough to fit inside a NES cartridge shell with a converter without difficulty.  Madara and Esper Dream 2, the other games that use the chip, do have translation patches.

Namcot 109/163

Rolling Thunder - Most Namcot 109/163 games with expansion sound are not very English friendly.  This game is basically the NES Tengen version with better sound.  Additionally, Namcot almost always used epoxy-bonded ROMs on their boards because they were cheap.  Unfortunately, this makes replacing these ROMs with translated ROMs on EPROMs very, very difficult.

NEC µPD7755C/µPD7756C & Mitsubishi M50805

The NEC ADPCM Speech chip was found in Jaleco's Japanese baseball games, virtually all of which were ported to the NES in the Bases Loaded series.  The chip stored and could play back voice samples on command.  Grab any one of them, games like Moero!! Pro Yakyuu are as common as they get in Japan, but realize its only a novelty.  Of course, the speech samples are in Japanese for the Famicom cartridge and English for Bases Loaded.  The NES versions had more PRG-ROM space to store the samples in ROM instead of on a special chip and used the NES's internal PCM channel to play them.  The Mitsubishi chip was found in Family Trainer 3: Aerobics Studio, which was similarly ported to the NES as Aerobics Studio.  Roll out your Power Pad for that one.

Famicom Disk System
FDS RAM Adapter + FDSStick
Read my review of this product for reasons why you should get one : http://nerdlypleasures.blogspot.com/2015/07/the-fdsstick-compact-solution-to-your.html

See also my list here of games for the Famicom Disk System where I give instructions how to clean the saves, all are easily accessible to English speakers : http://nerdlypleasures.blogspot.com/2015/06/cleaning-saved-information-from-famicom.html

Finally, I have generated a list of all Famicom and Famicom Disk System games that use expansion audio and were ported to the cartridge format :

Japanese Name	Expansion Sound Type	US Name
Gimmick!	Sunsoft 5B	Mr. Gimmick! (Europe/Scandanavia Release, US Proto)
Moe Pro! '90: Kandou-hen	D7756	Bases Loaded 3, Ryne Sandberg Plays
Moe Pro!: Saikyou-hen	D7756	Bases Loaded 4
Moero!! Pro Tennis	D7756	Rad Racket
Moero!! Pro Yakyuu	D7756	Bases Loaded
Moero!! Pro Yakyuu '88: Kettei Ban	D7756	Bases Loaded 2: The Second Season
Bio Miracle Bokutte Upa	Famicom Disk System	None (Japan Cartridge Release Only)
Doki Doki Panic	Famicom Disk System	Super Mario Bros. 2 (also Japan)
Dracula 2 - Noroi no Fuuin	Famicom Disk System	Castlevania II: Simon’s Quest
Egger Land	Famicom Disk System	The Adventures of Lolo (different levels)
Exciting Baseball	Famicom Disk System	Double Dribble
Famicom Golf - Japan Course	Famicom Disk System	Golf (different courses)
Famicom Golf - Japan Course Prize Card	Famicom Disk System	NES Open Tournament Golf
Famicom Golf - US Course	Famicom Disk System	Golf (different courses)
Famicom Golf - US Course Prize Card	Famicom Disk System	NES Open Tournament Golf
Gyruss	Famicom Disk System	Gyruss
Hao-kun no Fushigi na Tabi	Famicom Disk System	Mystery Quest
Hikari Shinwa: Parutena no Kagami	Famicom Disk System	Kid Icarus
Kaettekita Mario Bros.	Famicom Disk System	Mario Bros.
Link no Bouken: The Legend of Zelda 2	Famicom Disk System	Zelda II: The Adventure of Link
Metroid	Famicom Disk System	Metroid
Tobidase Daisakusen	Famicom Disk System	The 3-D Battles of the Worldrunner
Vs. Excitebike	Famicom Disk System	Excitebike
Zelda no Densetsu (Zelda)	Famicom Disk System	The Legend of Zelda (also Japan)
Family Trainer 3: Aerobics Studio	M50805	Dance Aerobics
Rolling Thunder	Namco 163	Rolling Thunder (Unlicensed Tengen Release)
Akumajou Densetsu	Konami VRC6	Castlevania III: Dracula’s Curse

Slipped by the NES Censor

Nintendo had a reputation of being a tough censor in the days of the NES and SNES before the establishment of ratings boards.  In these eras, the big-N implemented a modern day version of the Hays Code.  Who needed a video games rating system when every game has been vigorously inspected and cleansed to make it appropriate for children?  Nintendo controlled all licensed cartridge production, and if it did not approve a game then it would not be produced.  (It is a myth that Nintendo manufactured all cartridges, there are PCBs and chips in licensed US cartridges made by Konami, Sunsoft, Namco, Acclaim and Virgin Games).

Maniac Mansion is the best example of how Nintendo would control the approval process.  It required developers to send a prototype cartridge and a text dump.  Any objectionable content would be noted and sent to the company to fix.  Often, developers and publishers would engage in self-censorship to speed the approval process along.

References to sexual activity and nudity were not allowed.  Graphic, life-like violence was also forbidden. Language was to avoid words like "hell", "damn", "crap" and no stronger expletives were allowed.  Over time, Nintendo became more strict about what it would allow on its system.  Most of these examples given below were from the earlier years of the NES's development.

Nintendo of Europe was even more strict on violence.  Germany has long video games on its List of Media Harmful to Young People, the BPjM.  River Raid for the Atari 2600 was the first game on that list and it stayed there until 2002, so Nintendo games had to be very circumspect when it came to depicting any kind of realistic violence.  Thus games like Contra were given a sprite overhaul, replacing all human-like characters with robots and released a Probotector in Europe.  Unfortunately, because of the German standards, all of Europe suffered from this type of lowest common demonimator censorship.

Eventually, Nintendo's strict censorship began to work against it.  When Mortal Kombat for the Sega Genesis, which had the blood and graphic fatalities unlockable with a code, drastically outsold the SNES version, Nintendo began to realize the value of the ratings system.  Both companies and their eventual competitors submitted to the ESRB.  The sales for Mortal Kombat II, which was not censored, were better than the Genesis version.

Bionic Commando

At the end of the game, you must destroy the helicopter of the main villain of the game, "Master-D".  Master D's portrait had a death animation that was very graphic for the time.

Also, Master D's facial features obviously resemble Adolf Hitler's.  This is intentional because the original Japanese game, title : Hitler no Fukkatsu: Top Secret, made explicit that Hitler was the main villain.  While Capcom removed visual and textual references to the Nazi Party in the U.S. version, they kept Hitler's portrait unaltered.  Years later, when Wolfenstein 3D was ported to the SNES, not only were all Nazi references removed, but the posters found on the walls of Hitler were adjusted to reduce the resemblance to the Fürher.

Master-D also calls the hero a "damn fool" for challenging him, and "damn" is a Bad Word which shouldn't have made it into the U.S. release, but it did.

Castlevania

Level 3 of Castlevania features nude statutes in the background.  They may have been harder to notice on small TVs back running the NES video through an RF input back in the day, but the graphics were not changed.  By the time Konami ported Castlevania III to the U.S., the nude statute graphics were changed, but there were more examples of nudity in that game.

Eventually Nintendo would get around to removing crosses in the SNES era, but in the NES era, crosses were not particularly objectionable. All three Castlevania NES games have them, as does Zelda II: The Adventure of Link.

Castlevania II: Simon's Quest

We have the use of "Hell" in this game, right in the introductory text that scrolls if you do not press start at the title screen.

Golgo 13

The censor must have been asleep when this game was approved!  On at least two occasions during the game, Golgo 13 sleeps with female operatives he meets during the game.  He goes up to their hotel rooms after making prior arrangements, suggestive words are spoken, an animation shows the two coming together from their window, the lights go black and all your health is regained.  The voyeuristic view of the latter portion of the sequence only highlights the inappropriateness of this sequence by Nintendo's guidelines.   The Japanese version shows the ladies actually take their clothes off, showing toplessness.

In addition, this game is rather graphic when killing enemies in a first-person view.  When you shoot enemies, blood spurts from their heads.  This happens in the sniping sequences and the maze sequences.  At one point, you smoke a cigarette to regain health.  What kind of message did that send to the kids?

The enemy organization in the US version is called DREK, but in the Japanese original they are clearly identified as Nazis.  The file you obtain in the Greece Maze has a Swastika in the Japanese version and the true enemy is a cyborg version of Adolf Hitler, not "Smirk".  The US version keeps Hitler's likeness for "Smirk".

The sequel The Mafat Conspiracy: Golgo 13, is much more tame but does feature Golgo 13 smoking in the cutscenes and plenty of violence with Ninja Gaiden like cutscenes.

Kid Icarus

The statutes in world 4-1 are topless, as is the illustration of the Syren enemy in the game's manual.

The Legend of Zelda

The third Dungeon in the first quest is called "Manji" and the rooms are in the shape of a swastika.  This followed the Buddhist usage and faces counter-clockwise, not the Nazi usage which is usually clockwise and angled at 45 degrees.  The swastika had been in use in Japan for over one thousand years before Hitler appropriated it.

However, the counter clockwise version of the swastika was used by the Nazis, perhaps most notably as part of the standard for the 1st SS-Panzer Division Leibstandarte [bodyguard] SS Adolf Hitler after the fall of France.  No one complained about the use of the symbol at the time The Legend of Zelda was released apparently.  A decade later, parents did complain when the symbol was found on Pokemon cards and Nintendo announced that it would no longer use the symbol on Pokemon cards it released to the United States (and probably Europe) because of the negative cultural connotations.

Also, Link's shield and the Darknut shields have crosses on them.  Nintendo let religious symbols like crosses by in the early days.  

Magic of Scherezade

The boss of the second world, Curly, has obvious breasts.  "Curly" should really have been "Kali", the Hindu goddess of death, who is typically depicted topless and with six arms, which Curly's second form has.

Maniac Mansion

Although this game was heavily censored to remove objectionable content, Razor or Sid can explode Weird Ed's hamster by putting it in the microwave in the U.S. version.  Nintendo got wise to this and this act of animal cruelty was no longer possible when the game was later released in Europe.

Here is the original article "The Expurgation of Maniac Mansion", which describes what was left out and what was later removed from the game :

http://www.crockford.com/wrrrld/maniac.html

Metal Gear

In Metal Gear, cigarettes as a usable item, helpful when trying to beat the timed sequence at the end of the game where you must escape the building after beating the final boss before a bomb blows it up.  Smoking is bad, but in the NES era it was not high on the censor's priorities.  This would eventually changed as demonstrated by the cigarette item being changed to "fogger" in Metal Gear Solid for the Game Boy Color. The item still looks like a cigarette.

Ninja Gaiden

Ninja Gaiden has a rare use of the verb "to kill" when Foster is discussing the death of Dr. Smith.  Use of the verb "to kill" or any of its conjugations was strongly discouraged in the NES era.  In RPGs, a character is never "killed", usually they "died", were "slain" or "perished".  A party may be "annihilated".  This went to goofy levels when Final Fantasy II/IV's U.S. SNES release used the word "swooned".

Also, in Jaquio's lair and on his chest you can see six-sided stars, better recognized as a Star of David. During the NES and SNES era, Stars of David were frequently removed from RPGs like Final Fantasy and Final Fantasy II/IV, where they alluded to mystical abilities.  These were altered or removed for the Ninja Gaiden Trilogy release.

Ninja Gaiden II: The Dark Sword of Chaos

Similar to Ninja Gaiden, Jaquio has a pentagram (instead of a hexagram, maybe he lost a point because he died) on his chest.  This was altered for the Ninja Gaiden Trilogy. When you defeat Jaquio, his blood touches the Dark Sword of Chaos, transforming him into a demon.  The blood was turned from red to green in the Ninja Gaiden Trilogy.

Rambo

At the beginning of the game, Colonel Trautman tells Rambo : "You've got 36 hours to get in, complete your assignment, and get the hell out."  H-E-Double hockey sticks was a big no-no thereafter.

Ring King

Ring King has become particularly infamous for its in-between round animation of the corner men.  When looking at the animation, it is hard to find a non-obscene explanation.  The animation is not quite as suggestive in the arcade original.

I was too lazy to make an animated GIF, but there are no intervening frames.

River City Ransom

River City Ransom has a spa area where your character can recover his stamina.  The game shows you showering in Pop's Health Club, and among the graphics is a shot of your character toweling off his bare backside.  They show a dimpled butt.

Sqoon

Sqoon has a topless mermaid enemy, which appears on the title screen and later in the game.  This would not have gone unnoticed during a later period.

Taboo: The Sixth Sense

Taboo was practically unique in the NES library because it advertised on the box that it is not intended for children under fourteen.  Taboo is a tarot card reading simulator.  You input your name, date of birth and your gender, ask a question and the game will deal ten tarot cards and give you its interpretation of them. Among the cards that can be revealed are The Lovers, which shows rear male nudity and nearly-nude female nudity.  After it reads the cards, it will give you some "Lucky Numbers", asking you to select your state of residence.  The name/birthdate/gender screen has a cross and a pentagram.

This is a RareWare game, and I would suggest that only Rare's close relationship with Nintendo allowed them to publish this simulator.  Divination, occultism and fortune telling is offensive to Biblical Christianity.