The main objective of the game is to get to the exit of each level, while destroying enemies and collecting points. It allows many objects onscreen to be shot: obstacles, as well as enemies, can be destroyed by gunfire. Besides points, some collectibles include health powerups, gun powerups, and some inventory items with special abilities.

At the end of every level (with the exception of the last level in each episode), the player can receive up to seven 10,000 point bonuses, earned by making certain achievements in the level, such as destroying all cameras. At least two other Apogee titles, Duke Nukem II and Rise of the Triad, have similar end-of-level bonuses.