MSOIDS is a version of Asteroids with garish hand-scribbled art. Apparently made in four hours by messing about in MS paint and adding the results to a simple vector thinger, it makes an exceptionally tricky, eye-wincing version of the game. The madly scribbled explosions make it a special kind of bastard to get a hi-score at, but hey, you can press spacebar for new colour schemes.
Far more interesting, and developed in a mere seventy two hours by the same folk, is the nightmarish and crude puzzle FPS Mondo Medicals. The levels are "impossible" in that Escher way, and are a challenge to get past without becoming disorientated. Backtracking and going against intuition is key to defeating these spatial puzzles. (Why don't more games have spatial puzzles. And why aren't there more pure-puzzle FPS games? Eternal questions.) There's also an alarming pixellated horror theme, with a TV-faced man yelling about cancer, and some screaming maw thing motionless in a room. It's... unique.