This seems impossible but is instead impressive, clever and interesting!
It looks 3D but in a sense it’s a Dragon’s Lair pre-rendered forking video stream. Where the video is not only delta-compressed but rendered as executable code.
“This game has animated 3D solid graphics at 192x128, in 15 colours, at 16 frames per second, … which of course is quite impossible”
“If you run the compiler, you’ll see it render all the frames and calculate all the deltas, producing the ht.bin file. This can take 7 minutes, and will produce a file approximately 200MB in size, containing over 300 paths, a similar number of frames, and over 66000 compressed deltas.”
“The MTX code loads the delta from the disk, and then executes it.”
If you’re sneaky enough, you can get real time, colour 3d graphics out of the 9929 VDP
Another video, about how the machinery works, here: