DOOM64 Demake Brings id's Shooter to the Commodore 64

Doom has run on calculators, fridges and pregnancy tests, so a Commodore 64 version shouldn't be surprising. Still, DOOM64 from developer Kweepa is worth a closer look. The final version is now out on Itch.io, and it's not a straight port. Think of it as a careful demake that knows exactly what the old breadbox can and can't do.

Kweepa calls it the second entry in a planned trilogy of id Software conversions for the C64. If the name rings a bell, that's because he already got a version of Doom running on the VIC-20, Commodore's even weaker machine from before the C64.

Trading Angles for Height

On the VIC-20, Kweepa used off-axis walls, meaning walls that don't sit at neat right angles. For DOOM64 he dropped them completely. That sounds like a step backwards, but it wasn't. Without the angled walls, the C64 has spare processing time, and he spends it on floors and ceilings that change height dynamically.

That's a smart swap. A lot of what made the 1993 original feel like Doom was the stairs, raised platforms and sunken rooms. Flat corridors alone won't get you there.

Lighting gets the same creative treatment. The game redraws the machine's 40x25 text display with dithered shading patterns. Dithering mixes dots of different colours to fake shades the hardware can't show directly. The result gives rooms that moody, half-lit feel without asking the C64 for more than it has.

No Textures, and That's on Purpose

Here's the choice I find most interesting. Kweepa skipped full texture mapping on purpose. At the C64's resolution, textured walls would probably have turned into a muddy mess. Leaving them out also freed a good chunk of memory.

That memory went to custom lookup tables, mipmaps for the enemies (smaller pre-made versions of a sprite for when a monster is further away), and a soundtrack written for the machine itself. Choosing music and readable demons over smeared walls seems like the right call to me.

Built by Hand, Frame by Frame

The maps weren't converted automatically. Kweepa built them frame by frame on a grid in his own editor. It has instant preview tools, so he could balance elevation and shadows as he worked. That's slow, fiddly work, and it shows in how deliberate the project feels.

The weapons come from the PC shareware release of Doom. The sprites were tweaked by hand, given new palettes and rescaled to fit the C64. Sound effects come from the original PC speaker effects and were decimated, a sample-reduction trick that already worked for the VIC-20 version. So yes, expect your shotgun to sound a little crunchy.

Two Ways to Play

There are two builds to pick from. The standard version is aimed at modern emulators and hardware fastloaders such as the C64 Ultimate. The second one uses Krill's loader to squeeze the most disk speed out of a completely stock, unmodified C64. If you've still got the original hardware sitting in the cupboard, that's the one to grab.

It also comes with a nice loading splash screen by digital artist Paul Docherty, known as d0kk!. The release carries an AI disclosure too: AI assisted with the code.

Our Take

To me, DOOM64 shows that good retro demakes come from cutting things, not cramming them in. Kweepa decided what made Doom feel like Doom - height, light, sound, recognisable monsters - and dropped almost everything else. That approach seems to be spreading across the scene. We've seen people chase arcade and PC classics on 8-bit and 16-bit machines lately, from the AI-coded Outrun port on the Amstrad CPC to Defender on the Amiga.

The AI disclosure is worth noting as well. More homebrew developers seem to be using AI help for code and saying so openly, and it's worth watching how the community reacts.

What to watch next? The third part of the trilogy. Kweepa hasn't said which id game it will be, but given the two Doom projects so far, it'll be interesting to see what he cuts next time. In the meantime, C64 owners have plenty to play, including the Giger-inspired shooter Void Lancer.