New article title in a few words
If this weren't a C64 port of the legendary Wolfenstein 3D, we probably wouldn't dedicate an entire article to it. By today's standards, Wolf64 is more of an impressive technical demonstration than a genuinely enjoyable game. But the C64 community has been fascinated by these seemingly impossible ports for decades. And in 2026, Kweepa demonstrated that Wolfenstein 3D could be brought to life on an original, unexpanded Commodore 64.
No hardware tricks: Running at 1 MHz
The game runs on an unexpanded C64, without an external processor or REU. The engine is written in 6502 assembly and uses raycasting: it casts rays for each screen column, then calculates the apparent height of walls based on the distance to the intersection.
- + 38 × 40 display area using a specially designed multicolor rendering technique
- + 64 × 64 level map with compressed and reused elements
- + Precomputed lookup tables instead of multiplication and other computationally expensive operations
- + Uses up to all eight hardware sprites to display the weapon
When even a few CPU cycles matter
According to the publicly available source code and the TechNotes, the wall renderer uses separately generated routines for different wall heights. The 6502-specific optimizations include page-aligned jump tables and pre-shifted texture coordinates. This is optimization at a level where even a single instruction matters.
One of the community contributors, Bigfootbrz, reworked the wall renderer. According to Kweepa, this shaved 8-15 ms off the rendering time of each frame and freed up nearly 5 KB of RAM. For a game running at roughly 5-10 FPS, that's a very noticeable improvement.
Clever compromises
- + Enemies are only updated and rendered when they are close to the player
- + Previously calculated wall distances help hide objects behind walls
- + Textures were manually adapted to the C64's color palette
- - The original PC Speaker sound effects sound absolutely terrible on the SID
- - Don't expect PC-level performance: early measurements suggest something closer to 5-10 FPS
- - Memory limitations meant that some graphical elements and enemies had to be simplified
Another unusual aspect of the development is that Kweepa openly acknowledges relying heavily on AI tools for code scaffolding and data conversion. However, he remained in control of the algorithms and technical trade-offs. The first playable version was completed in less than a week.
But is it actually playable?
Yes. Version 2.1 already includes an F1 map, quick save and quick load, mouse support, and two-button joystick controls. It's available as a D64 disk image and an EasyFlash CRT cartridge image. However, quick saving doesn't work in the disk version using the Krill fastloader.
Game: Wolf64 - itch.io | Source code: GitHub | Technical background: Kweepa's development log