All Things Devours

This game is exactly one puzzle--but what a puzzle. If you like your puzzles logical, requiring in principle no more than strict deduction from a complex set of premisses, then you will love this game. Once you've found out how the game world works, there is nothing arbitrary anymore; there are no intuitive leaps, no bizarre associations; you just need to think carefully. The effect is a little like a chess puzzle, where'll you try out some moves, notice what goes wrong, think deep and hard, and finally arrive at the solution.

I highly recommend it.