Earthworm Jim: DOS & Windows Versions

Originally released for the Sega Genesis and the Super Nintendo (SNES), Earthworm Jim has been ported to other systems, such as the Sega CD (Earthworm Jim: Special Edition) and PC. Both DOS and Windows versions were released, which in itself was common for the time, but as they were ported from different console versions (rather than from each other), interesting differences exist.

The Windows version was ported from the Sega CD “Special Edition”, and includes all of its extras. The DOS version, as far as I know, was never released separately, but only in a bundle with Earthworm Jim 2, sometimes known as The Whole Can O’ Worms. It was actually released after the Windows version, but was based on the earlier console versions, and does not include any of the Special Edition stuff.

I’ve played the DOS version many years ago, and having heard much about how the Windows port is superior, recently decided to give it a try, and do a head-to-head of the two. For a more detailed comparison of all other releases (including the sequels and the 2009 Earthworm Jim HD remake, I recommend this excellent Hardcore Gaming 101 article and this video showing the game played, in parallel, on various consoles and the PC.


The Windows version contains two levels omitted entirely from the DOS release – the Sega-exclusive Intestinal Distress and the Special Edition-exclusive Big Bruty. The Special Edition content also includes a few extra sections in existing levels:

  • New Junk City has a whole new section featuring Jim as a naked worm (like in Level 5), and the boss battle (with Chuck) takes place at the end of this second section. There are also new secrets and bonuses throughout the level.
  • The mid-level boss fight with Snowman in What The Heck has been extended to include an actual sub-level, and not just the arena.
  • The second part of the Mecha-Chicken battle (“Chicken Plummet”) at the end of Level 5 was removed from the DOS version, even though it was not a “Special Edition” exclusive and was present in both SNES and Genesis versions.

There are many differences in other levels. Some have potentially significant impact, such as in the Pod Race level, where the secrets are completely different, or the final boss fight in Buttville which is much easier in the DOS version. These are further elaborated on the tips page.

The Special Edition also includes a unique weapon – homing rockets (similar to those seen in Earthworm Jim 2). They are not common, and appear mostly in specific levels – for example, What The Heck and Big Bruty. Zapping those annoying devils and wasps is easy and super-fun with these. All in all, there is quite an amount of extra content in the Windows-based Special Edition.


The original resolution of the game is 320×224. The DOS version also has a 320×240 mode which is more compatible, but runs at a lower frame rate (60Hz vs 72Hz). Unless you are running actual DOS on real hardware, the difference is probably negligible. The DOS version runs naturally in fullscreen mode, or expands to the limit of the emulator’s window (if you use DOSBox or the like).

The Windows version has two bult-in modes: 320×224 and 640×480 (actually 640×448 – a simple doubling of the original resolution). The window can be stretched basically to any size, including maximized, but it will merely scale and/or stretch the original 320×224 output. There is a fullscreen mode as well, but getting it to work on modern systems is tricky (some workarounds are described here). Stretching the window while preserving the aspect will be good enough in most cases.

The animation in the Windows port is noticeably smoother, largely due to the addition of extra sprite frames in the Special Edition, and the faster game speed.

In most levels there are various differences in the background, or the colors. Both games use 256 colors, but in most cases (not all) I felt that the DOS version had nicer gradients and overall slightly better appearance. Comparative screenshots of the different levels for your consideration are posted throughout this article.

In the dark secret level Who Turned Out The Light(s)?”, the DOS version renders Jim darkened, rather than fully black with only eyes visible; as a result, some sections may be slightly easier.

Sound and Music

The sound effects are identical for the most part, but the Special Edition adds some extra voice effects of Jim, such as: “I’m a rocket man!” (Andy Asteroids), “I’m nude” (naked worm segments), “Sharp!” and “Thorn!” (in Buttville) and “That’s the queen!” (when encountering the final boss).

For music, both releases use the higher-quality Redbook audio tracks of the Sega CD Special Edition, which is great (and you can listen to them in a CD player). The music tracks are mostly the same, but there are differences in arrangement. The songs for most of the levels loop two-three times per track, supposedly to minimize spin-up when a track is restarted. The Windows version attempts to make the tracks sound like one long piece, cutting the pauses and sometimes intro/ending between the two loops, but the DOS version keeps the pauses (and sometimes fadeouts). The Windows version does not stop the music as Jim reaches the end of Andy Asteroids, so it plays over the special end-level tune.

The DOS version has the tracks for Buttville‘s descent part (“use your head”) and second part (main level) switched, compared to Windows and every other version I know. The original Nintendo / Sega releases actually switched the music back to the “descent” song during the final boss battle, but the Windows version doesn’t do it, so neither is consistent with the consoles in this regard.

The ending music, as well as the funny extra voice-overs, are also CD audio tracks. They are slightly different between the two releases (more on that below).  For some strange reason I could not figure out, the Windows CD also has 11 short tracks that are nothing but the announcer saying “Earthworm Jim”. The DOS CD does not include the music tracks for the missing levels, which is expected.


The DOS version kept the console-style main menu, where you can configure the difficulty, controls or input level passwords. There aren’t any graphics/sound configuration options – instead you can press ‘S’ in game to toggle sound effects, and F3 to switch between 200 and 240 vertical lines (the latter is preferred for visibility, the former may be faster on slower PCs). You can press F5 to display (X,Y) coordinates.

The Windows version has a traditional Windows-style configuration menu for sound, graphics, controls and difficulty. The game window’s status bar also has convenient shortcuts to each of the configuration tabs, and you don’t have to stop the current game to configure most of them, which is nice.

If you idle at the main menu, the DOS release will roll the PC version credits; the Windows port has a funny pencil-drawn animation of Jim. Eventually, both versions start showing demos of certain levels.

Both versions allow you to start on any level you’ve reached, and play them in any order. The Windows version simply unlocks each level in the menu after you got to it once, which is very convenient. The DOS version has a password (“passworm”) system for each level (see here), which is less convenient since you need to have them memorized / written down. Starting on any level gives Jim the default number of lives (2, 3 or 5 – for easy, normal and hard difficulties) and the default number of continues for each difficulty.

Progression is separate for each of the three difficulty settings, so you cannot change it mid-game. The Windows version remembers how far you’ve gotten on each difficulty; the DOS version simply has different passwords. One advantage of the DOS version is that it certain sublevels have passwords of their own, so you can start on them directly: the Who Turned Out The Light secret level, the Naked Worm subsection of Level 5, the Mecha Chicken boss fight, the main level of Buttville (skipping the descent) and even the PsyCrow sections of Andy Asteroids (which normally only appear if you lose the race).

The level intermission screens look slightly different between the two versions: the Windows port shows the main villains you will encounter in each level, which is a nice touch. The DOS version shows the password of the level.

‘P’ in DOS or ‘Pause’ in Windows will pause the game. The Windows version also pauses automatically when the window loses focus, which is great for not dying after switching to a different program accidentally, or if you are on a laptop that doesn’t have a ‘Pause’ key.


Replaying Earthworm Jim after many years I was surprised to realize that the controls are really so-so. Not the controls per se, but the combination of responsiveness, collision detection and platforming mechanics. Firing or whipping need to be very precise (and often appear to miss direct shots). Jim’s hitbox feels very large and he seems to easily take damage from different angles, which momentarily stuns and bounces him around, making control difficult. Platforming is also not easy: last-moment precision jumps and catching ledges feels hit-and-miss. After some practice, I usually get the rhythm right and the game flows better, but I can never feel quite sure whether the difficulty is intentional or due to poor programming.

The DOS version suffers from the same general problems, and somehow makes them worse, due to the vastly different feel of the controls. While the Windows controls are generally responsive, mostly similar to the feel of the console versions (as far as I could test), I would describe the DOS controls as “stiff”: you really need to push the buttons hard, hold them for longer and time the combos (such as jump and swing or helicopter) much better to get the desired result. The physics have also been tampered with: Jim feels heavier, running jumps at the very edge of platforms tend to fail (think Prince of Persia), getting an ideal running jump is much harder, and the jump range seems slightly lower overall, both vertically and horizontally. Also, the DOS port does not allow you to hang off ledges without climbing immediately (something that can be done in the Windows port and all console versions by holding down on the controller).

You would think all this totally breaks the game, but, surprisingly, it doesn’t. While a few locations are certainly more frustrating at first, after some practice I realized that I can adjust my game to the handling (kind of like adjusting to steering a heavy car versus a light one), and still do well. Yes, I even managed the “Advanced” section in For Pete’s Sake with the DOS controls. So far I found just one (optional) location that may be unreachable due to the different jump physics (or due to a bug).

Phenomenally, there are even places where the DOS version feels better, such as Andy Asteroids levels, and various random spots along the game where I felt the collission detection worked better or timing was easier (perhaps due to the slightly slower game speed).

Key assignment and controller support

The Windows version does not allow special keys (Ctrl, Alt, Shift, Tab) to be assigned to actions, whereas the DOS version has certain letters reserved which cannot be used: ‘S’ (toggle sound effects), ‘M’ (toggle music – something which never worked for me), ‘P’ (pause), ‘J’ (toggle joypad) and ‘R’ (recalibrate joypad). The DOS port allows a key to be assigned to “weapon cycle”, which is a bug, since you cannot switch weapons in Earthworm Jim, by design. It was probably picked up in error from the Earthworm Jim 2 code, where such a function is available.

For those who prefer playing platform games with a joystick/gamepad, the Windows version is said to have much better support for it, with fewer glitches (being a keyboard player, I never verified this).


Most of the differences in gameplay are due to bugs in the DOS port; some are arguably not bugs, but deviations from the behavior established in the console versions. Here is what I have found:

  • The damage inflicted by most spikes has been massively scaled down in the DOS port. For example, the spikes in What The Heck and the thorns in Butville only inflict 5%-15% of damage, depending on difficulty, rather than 30%-50%. A lot of segments are much more forgiving this way.
  • Also in the DOS port – certain events are not reset, which makes the game easier at least in two ways: (1) Items that appear due to triggering swirls of light in specific points stay put, and you do not have to trigger them again if you die. (2) In Pete’s Sake, asteroid showers are a one-time event; once you trigger one of them, it will never happen again, even if you get pulled back and pass the same section.
  • The biggest bug in the DOS version: damaging surfaces are not solid and Jim can “no-clip” through them. In some spots it makes them extra-dangerous, as you can fall through them to instant death; in others it can be exploited to skip some part of levels or do otherwise impossible things (see examples on the level hints page).
  • One bug that’s actually in the Windows version, but not in the DOS one is the ability to finish the “Advanced” route in For Pete’s Sake by simply reaching the right edge of the level with Jim, even if Pete hasn’t reached his house. This can be exploited to skip some of the last obstacles, by whipping him backwards and running fast towards the end, before he gets angry and catches you.


The Windows version has three different endings depending on the skill level you beat the game on: ‘Easy’ doesn’t give you the ending at all, just a hilarious fake recitation of ‘What are worms?’, where scientific facts are mixed with jokes and general nonsense, followed by a funny reading of the credits. ‘Normal’ and ‘Hard’ show the actual ending, and ‘Hard’ also gives you a special congratulation (‘You’re the best!’).

The DOS version combines the funny and the real ending into one; regardless of the difficulty level, it starts with the real ending (complete with music), transitioning to ‘What are worms?’, in a slightly different rendition (you also don’t get the funny text, just the voice-over, while the normal credits are rolling). Finishing the game on ‘Hard’ gives the ‘You’re the best!’ pep talk as well, before the ending.

The Special Edition has the cow-on-top-of-princess sprite flipped, so that the cow is facing Jim. In the DOS version, the cow and princess fall into lava before the credits, not after. The DOS version credits are accompanied by various sprites of Jim. In both versions, Jim sneaks back to grab the princess’ crown at the end.


The Windows version is designed to be run directly from the CD – all settings and game progression is stored only in the registry with no files copied to the hard drive. On modern operating systems you may still need to copy the game files and replace one DLL, as explained below. In addition to the game, there is also a Microsoft Plus! theme (custom wallpaper, cursors and sounds) that can be installed or uninstalled through the CD’s Autorun program.

The DOS CD, in addition to the basics (game, installer, setup program to configure the sound device and Readme file), has a Windows installer (possibly configuring a PIF file for the game to run under Windows), and two movies – an “Earthworm Jim” song animated flick, and a Playmates “Earthworm Jim” toy line showcase. Both are DOS executables and require a 16-bit subsystem to run.

Cheat Codes

The cheat codes are different between the two versions, and the Windows version has many more of them. Consult the codes and cheats page.


Compatibility is one area where I feel the DOS version has an edge: with a modern DOSBox build you can play it pretty much as intended on any system, and the setup is relatively hassle-free. You get fullscreen modes with a choice of various scalers to reduce pixelization, and if you prefer to use a controller, the built-in mapper allows controller buttons to be assigned to emulated keypresses, avoiding the need to mess with the game’s limited joypad support. I suspect that the relative simplicity of setting up the DOS port is why GOG chose to offer it in their bundle, instead of the Windows version (to the dismay of some fans).

The Windows port is not bad in terms of compatibility: originally intended for Windows 95, it is impressive that it can still be played even on 64-bit Windows 10. It is not a hassle-free experience, but the PCGamingWiki entry has workarounds for the most common issues. The application should be configured to run in Win9x compatibility with the updated WAIL32.DLL (otherwise sound effects will not work or the game will crash), and in 256-color mode (otherwise colors may be messed up occasionally). When using a CD image on a PC with an actual CD drive – disable/reassign the physical drive letter (because the game is hard coded to look for the disk in the first CD-ROM drive).

Even with the workarounds, on some systems I encountered a glitch where sound effects stopped working in mid-game (happens most frequently during level transitions); the solution is to disable them, and then enable them again, which is doable, but a bit annoying.


Which of the two versions is better? Clearly, the Windows port is superior for the extra content, faster speed, smoother animation, more responsive controls (usually), friendlier configuration interface, and better cheat codes. I don’t think (as some do) that the DOS port is terrible, but its advantages – slightly better graphics, sub-level passwords and the somewhat easier setup to get a consistent experience on modern systems (via DOSBox) – generally do not compensate for the shortcomings.

While working on this article, I found myself replaying both ports multiple times. On some days I thought “Windows version, hands down”, but on others I was able to appreciate that the DOS version, after a one-time setup, just works. Sound effects don’t cut out randomly, it looks better in full-screen (aspect-corrected by DOSBox, with optional smoothing filters) and has enough little differences to provide a unique and interesting experience, once you adjust to the odd controls. I believe that a PC gamer with appreciation for retro classics will benefit from both in his collection. Hopefully, this write-up captured the important differences, for players to know what to expect.

Earthworm Jim 2

Since I mentioned the Earthworm Jim 1&2 bundle a few times, here are a few closing words on the PC port of the famous sequel. On the PC, it was only released for DOS (you can get it in the same GOG bundle), but the port quality was much higher – animations, controls and gameplay feel much tighter (again, with high quality CD music). Sporting better graphics than contemporary consoles, it could be considered the perfect version of the second game among all, except, for reasons unknown, it’s missing the second level of the original SNES release – Lorenzen’s Soil.


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