Powerslave is a first person shooter with an arcade style level progression. There are 20 consecutive single-player levels and 12 multiplayer deathmatch levels.

Unknown alien forces have invaded the city of Karnak, and isolated it from the rest of the world. The inhabitants were subjected to torture, or injected with a substance, turning them into servient mummies. Even the mummy of king Ramses was not spared. After multiple failed attempts from world leaders to send armed forces to deal with the situation, you were chosen among a select few of the world's best special forces to infiltrate Karnak and destroy the invading forces from within. The mission turns awry, however, when your helicopter is shot down, and you find yourself alone, hoping to complete your mission and get out of the fray alive.

Contrary to the later console adaptations of the game, each of the 20 singleplayer levels are played back to back with the player hunting for keys and secret areas to proceed onto the next level, similar to other games of the time, such as DOOM. The game features a single save slot for each playthrough and has a checkpoint system, allowing the player to continue from the latest checkpoint they have found. Levels range from ancient cities and temples through sprawling caverns of also lava variety all the way to the alien Kilmaat ships, and are filled with traps and keys hiding multiple pathways from initial access.