Darwin is a life simulator type of game.  Altough it is in B&W, it features pattern filled rectangles to account for up to 8 different "species" competing to survive in the arena.  

In Despair, you have a (renewable at will) group of helpless victims and many tools to torture them. That's it, have fun.

Dogfight is a mid-90s flight simulator in which you try to shoot down your computerized opponent with your plane. Alternatively, you can play with a friend over a network. That's pretty much all there is to it. Have fun!

DopeWars is a drug induced err... related strategy game. You start in debt to Louie the Fish and your goal is to repay the debt before the loan shark breaks your limbs. After your debt is paid off your goal is to make as much money as possible by...