Asteroids

Asteroids was originally an arcade machine by Atari, 1979. It can probably be seen as a spin-off of Space War, which is not very well fit for arcade usage. The player still controls a spaceship which more or less follows the laws of physics, but instead of a duel with another spaceship has to shoot—and avoid—the asteroids floating across the screen. Periodically there will be a flying saucer too, which shoots at the player. The modification was very successful: The one arcade machine based on Space War was completely forgotten, but Asteroids became Atari's best selling coin-op of all times.

The two games are still similar enough that there is at least one Windows game (Space War!) that can be played as either.

Asteroids for DOS