Fetus is a strange, dark little platform/puzzle game. No story is complained, but what you have to do is introduced to you during the first few levels.
Each level ends when you hit the big TV, which warps you to the next level. Using just left and right (no jump!) you have to negotiate your way around the platforms. Each one room level is like PacMan - leave the the edge of the room, and it wraps round to the other side. This is also true of falling. Both of these are methods to get around impossible obstructions. There a switches that need to be switched, Lasers which need to be blocked or avoided and gravity-reversing pads, which allow you to approach segments upside-down if need be.
The introduction is done very well, and you are gently introduced to the mechanics of Fetus. However, one this phase is over, the puzzles start to get really complicated! It's much more a puzzle game than a platformer really, and it doesn't at all reply on reactions or speed, but problem solving. If you like puzzles, you'll enjoy Fetus, but you'll have to get used to the very retro 8-bit like graphics and extremely minimal sound effects
If you don't mind the retro graphics and sound, there's a very payable, unusual platform game in Fetus that'll really get your brain working.