In the game, you fly around a planet and collect valuable trimetalisium energy crystals while destroying all the enemy fighter drones you encounter. Making the game challenging is that collecting crystals means that you'll have to land your ship on the surface and risk being hit from above by the drones since you can only move vertically when you're down near the surface.
This game provides examples of
- Collision Damage: On the hardest difficulty level, colliding with an enemy drone destroys your ship.
- Difficulty Levels: Three, with normal and hard modes for one or two players. Easy mode (one player only) has unlimited ships and no scoring.
- Endless Game: You play until you run out of ships, or (in easy mode) you just get bored.
- Power Crystal: The trimetalisium energy crystals that you must collect, although they don't really do anything for you except increase your score.
- Scoring Points: For ramming or shooting the enemy (except in hard mode, where you must avoid ramming the enemy), and for collecting crystals. Easy mode has no scoring.
- Shoot 'Em Up: Similar to Defender, but with only one enemy on the screen at a time.
- Video-Game Lives: Four, except in easy mode, where you have unlimited ships.