Anyway, the idea then transmogrified - the kind of games that already use this "simple shape" theory are all the old classics - Breakout, Pac-Man, Tetris. Their graphics were nothing special but they were good games. So how about a game set inside another game? Maybe this screenshot will give a better idea of what I mean:

Those blocks are supposed to be the blocks in a game of Breakout. I intend to have a bouncing ball and maybe the puck. The player would walk around in an FPS-stylee, and maybe shoot all the blocks while avoiding the puck or something.
I even got as far as starting a Pac Man level:

I think it was this level that started eroding my enthusiasm. I realised that this game is going to take a lot of time to create all the 3D models for each level/game. Then there's the AI for all the unique enemies, the level design etc etc...
So I decided to (maybe temporarily) abandon it in favour of another game idea; an idea that uses simple graphics, no advanced AI, and is incredibly addictive. As soon as I have this idea, I'll let you know. Meanwhile, it's back to the Spectrum Arcade for inpiration.