Ah yes, Lode's raycaster tutorial, the classic writeup keeps generating interesting projects. Such as this one.
The human ingenuity never ceases to amaze me. Take what's essentially a pong machine with a few extraneous bits and almost no memory, what you can do with it? Apparently racing games, building games, maze games, even honest to god space sims.
The 2600 VCS is really interesting. It didn't even have a framebuffer, so painting pixels was done scanline by scanline and you had to be done with your scanline in a certain amount of CPU cycles, which meant you had to count them and know which instruction took how long.
It only had 128 bytes RAM, that's bytes, not KB.
A real technical marvel is the chess game for the 2600. Since the sprite capabilities were so primitive, they couldn't even draw all pieces in a single scanline, they had to alternate scanlines so that they could even draw all chess pieces, and that's not even mentioning the fact that they somehow made a chess playing algorithm work in 128 Bytes of RAM.