Spasim is a First-Person Shooter for up to 32 players, in four teams of up to 8 players each. The first version was a simple Shoot 'em Up with phasers and torpedoes. The second version added home planets, space stations, and resource management. Teams had to work together in order to reach a distant planet filled with resources, while preventing rebellions on their home planets.
Spasim inspired Silas Warner to write a 3D dogfighting game called Airace, which evolved into Brand Fortner's Airfight and then into Sublogic's Flight Simulator (now Microsoft Flight Simulator). It also inspired John Edo Haefeli to write a tank game called Panther, which evolved into Atari's Battlezone.
Spasim provides examples of:
- First-Person Shooter: Originally a simple multiplayer Shoot 'em Up, more depth was added later.
- Player Versus Player: Up to 32 players in four teams of eight players.
- Polygonal Graphics: The Trope Maker for true 3D videogaming, as opposed to the Faux First-Person 3D of Maze War. Spasim's graphics are very simple, wireframe without hidden line removal.
- Ray Gun: Phasers.
- Shout-Out: Ships and weapons from Star Trek.