This is basically a Wolfenstein-like ray-tracing engine for the C64, which seems to be amazingly memory efficient and rich in functionality. In fact, it seems to be capable enough to make an actual Wolfenstein-style game on the C64.
It is also EXTREMELY slow on a real C64. In fact, even on a SuperCPU, or in VICE running in warp-mode on my i7 Mac, it is still quite slow.
What is very nice is that the author appears to have added support for the MEGA65.
Here is a video of it running on the MEGA65 at 48MHz. Compared to my 2.7GHz i7 Mac running VICE, the MEGA65 is somewhere between 2x and 5x faster, as far as I can judge. It would be great if the demo included a frames per second measure, so that we can benchmark more precisely. It would also be great if someone with a Chameleon could test it on there, so that we can get a sense of the relative speed between the Chameleon and current MEGA65 state.