The Horrible Pyramid

Starts off like Infidel: you're an archaeologist investigating an ancient Egyptian pyramid, scooping up treasures wherever you find them. BUT things go in a different direction very quickly. And it has to be very quickly, as the game is over in around 10 minutes. But it compresses a lot of fun and quirkiness into that bite-size framework. Good writing, simple puzzles (and one poorly implemented one involving a door - acknowledged as poorly implemented in the source code), and a rather predictable (but well-done nevertheless) twist.