Monday, December 26, 2016

Community Produced DOS Game Enhancement Hacks

In the past several years, ambitious and talented programmers and hackers have made some substantial improvements to some classic DOS games.  Here in this blog entry I will highlight some of the hacks I consider to be the most impressive or most useful.  I am particularly interested when elements of a game, such as unique sound effects, that could have been experienced at the time of the game's release in a less than ideal way have been added to the DOS versions of these games.

This is not intended to be a comprehensive list of every hack out there.  I am not including simple speed fixes or DOSBox compatibility patches.  I also am not including any hack which I feel violates the "spirit" of the original DOS code.  Some of these hacks are more involved than others, but I wanted to give an overview of what kind of hacks are out there.   Some of these hacks are nearly 10 years old, but all were given to an organized community of vintage computer and DOS gaming enthusiasts.

Monkey Island 1 & 2 Ultimate DOS Talkie

In 2009 LucasArts remade The Secret of Monkey Island and released as The Secret of Monkey Island Special Edition.  They ported the game to Windows, redrew the graphics in high resolution and added full voice acting and a revised orchestral musical score.  The voice artists included Dominic Armato as Guybrush Threepwood and Earl Boen as LeChuck, both of whom had performed these roles in The Curse of Monkey Island and Escape from Monkey Island.  The remake also included the DOS CD-ROM version of The Secret of Monkey Island and allows you to switch between each version on the fly.  The DOS CD-ROM version as played in this Special Edition does not contain voice acting.

In 2010 they did the same thing for Monkey Island 2: LeChuck's Revenge, releasing it as Monkey Island 2 Special Edition: LeChuck's Revenge.  As MI2 did not have a DOS CD-ROM version, LucasArts let you play the floppy version but added the voice acting.  Again Armato and Boen were brought back for their iconic roles.  This was one of Boen's last acting roles before he retired (he played Dr. Silberman in the first three Terminator movies.)

I bought the SOMI SE when it was released on Steam.  Sometime between the two SE releases, a patch was released to add the speech and some of the sound effects back into the SOMI DOS CD version.  A side effect of the patched game when used with DOSBox or real DOS is that the game relies on a sound card for music (Adlib, MT-32, General MIDI) instead of CD-Audio.  The SCUMM interpreter used did not support CD Audio and digital audio.  There are a few tidbits of lines here and there which had no corresponding SE speech, but otherwise the game plays the audio as if a true talkie DOS version had been released in the mid 1990s.  MI2 SE later got a patch to add speech back into the real DOS floppy version.

In order to ethically apply the patch, you need to purchase the Special Editions from Steam of GOG. I always prefer GOG to Steam because the former never uses DRM.

Dune Generic OPL3 Support

Dune for PC's sounds best with an Adlib Gold.  Dune is one of the relatively few games that do not rely on widely available middleware sound drivers to support the advanced features of the OPL3 chip.  The OPL3 chip is found on the Adlib Gold, Sound Blaster Pro 2.0 & 16 and the Pro Audio Spectrum/Studio 16.  Dune only supports OPL3 features, including stereo separation, on the Adlib Gold.  This patch allows the game to support OPL3 features on any card with an OPL3 chip at the standard Adlib/Sound Blaster ports.  The patch does not and could not give you the reverb features of a reverb-daughterboard equipped Adlib Gold.

The patch only works on the floppy version of Dune.  The talkie CD-ROM version of Dune keeps most of its files on the CD, making it more difficult to patch.  While the CD-ROM version supports the Sound Blaster Pro, it only uses single OPL2 features and mono output with it.  However, the CD-ROM version does not support the digital audio features of the Adlib Gold, so you need a Sound Blaster compatible card to hear the speech.

Silpheed PS/1 Version to Standard PC Hardware

Silpheed for DOS as commonly available (versions 1.0-2.4), supports many audio devices for music but the sound effects, including the blasts of the lasers and Xacalite's speech, only support the PC speaker.  The sound effects are few and far between and Xacalite's PWM-style PC Speaker speech was so awful that they added subtitles in version 2.0 and above.

There was a special version of Silpheed (v3.0) released alongside the IBM PS/1 Audio/Game Card that supports digitized audio.  Xacalite's speech is clear and there is more speech in the game.  Laser blasts sound much more impressive and there are explosion sound effects added.  While this version supports some of same music devices as the older versions. digital audio is supported only through the Audio/Game Card's proprietary DAC hardware.  The Audio/Game Card only works with two computers, the PS/1 2011 and 2121 and is a very rare card.  Finding a copy of Silpheed version 3.0 legitimately won't be easy.

The patch adds support for digital audio with a Sound Blaster card and supports a combination of the MT-32 for music and the Sound Blaster for digital audio.  It also allows joysticks to work through a standard gameport.  The Audio/Game Card had a standard PC-compatible gameport but also included advanced features as well.  It also allows you to use a UART compatible MPU-401 instead of the proprietary MIDI interface of the Audio/Game Card.  Finally, it supports stereo music with an OPL3 chip.

Commander Keen 4 & 5 Composite 16-Color Patch

Commander Keen 4 & 5 are two of the very few games of the "shareware revolution" that supports CGA.  They only support standard Mode 04h CGA using the default cyan/magenta/white palette in high intensity.  In other words, the CGA versions of these games look just like most games of this time period.  Nonetheless, given the smooth diagonal scrolling that the EGA version boasted, it was a miracle that the CGA version exists at all!  John Carmack, the main programmer of the game, did not even know about composite CGA color and seemed to appreciate the effort of the patcher.

This patch changes the Mode 04h CGA graphics into composite Mode 06h for a wider choice of colors when displayed on a composite color monitor or color TV.  High resolution composite color can give a color palette much closer to the 16-color RGB EGA palette these games ideally use.  You need a true IBM CGA card to be assured that the colors will be correct.  The Epson card I discussed here : will show a somewhat different palette.  The patch programmer used an early IBM CGA card, which has some hue variations compared to late IBM CGA cards (purple to red being the best example.)

CK4 and CK5 have separate EGA and CGA versions.  Commander Keen 4 was originally shareware for Commander Keen 5, and the EGA or CGA version of CK4 can be freely downloaded.   CK5 was only a retail product, and its CGA version can be a bit hard to find legitimately and will take some searching to find otherwise.  CK4 and 5 really need a 286 to shine, especially when CGA has no dedicated scrolling hardware, unlike EGA.

While there is a "CGA" patch floating around for Commander Keen 1, which probably also works with 2 & 3, it really just limits the palette to the three colors used by CGA palette 1 in high intensity (cyan/magenta/white) plus black.  You still need an EGA or VGA card to run the game, which doesn't quite mesh with the spirit of this article.

Tomb Raider Audio Restoration Patch

I previously described this patch in this blog entry and gave links to downloads and instructions here :

Wolfenstein 3D 8086/8088 Recompiled Executable

The official versions of Wolfenstein 3D for DOS will refuse to run on any processor less advanced than a 286.  Any machine with an 8088, 8086, V20 or V30 CPU is out of luck.  This patch will allow Wolfenstein 3D to work on any of these CPUs.  However, unless you have a super fast turbo XT, 10MHz or better, preferably a V30, the game will run in a slideshow.  Moreover, only with the world record holders for system speed will be able to run Wolf 3D tolerably in anything larger than the smallest graphical window the game allows.


What about the various patches for the Ultima games?  I do not consider most of them appropriate and do not listed because they require a DPMI extender like DOS4GW or DOS32 or CWDPMI to run.  Using a 32-bit DOS Protected Mode Interface Extender violates the spirit of these games, which were made to run on an 8088 or a low speed 286.  You almost completely lose sound effects when running these upgrades because the sound effects rely on the system speed and expect a low speed.

There are more hacks out there.  You can peruse these threads here :

and here :

but be prepared to spend some time reading up on these patches.


  1. Nice post! BTW, when did the first mods (not just hacks) appear?

    And will you ever write something about overclocking old hardware?

  2. How can you get the silpheed patch to work? I copied over the files into my game folder, configured the game to use mt32, and it still plays the digitized audio through the pc speaker. (running DosBox configured with munt).

  3. That's because you don't have Silpheed's v3.0 version, which contains files with speech samples.