PySpaceWar

Two ships duel in a gravity field. Gravity doesn't affect the ships
themselves (which have spanking new anti-gravity devices), but it affects
missiles launced by the ships.

You can play against the computer, or two players can play with one keyboard.
There is also a Gravity Wars mode, where the two ships do not move, and the
players repeatedly specify the direction and velocity of their missiles.

WWW: http://mg.pov.lt/pyspacewar/