The game presents an isometric point of view of different interconnected, maze-like rooms that the player passes through floor by floor. Each room can require brains, brawn or both. All bioweapons present in a room must be killed and all air duct vents that they enter through sealed before proceeding further. The building's paranoid security system has predictably gone haywire, leaving rotating grenade launcher turrets, land mines, electrified floors and laser fences targeting humans. Less hostile puzzle elements are doors, the switches and computers that control them, keycards, infrared electric eyes and teleporters.
The courier is soon armed with a laser gun that holds unlimited ammunition and a great puzzle value: its shots bounce off walls, trip switches and travel in teleporters. Finally, surviving Genoq employees and some special items are scattered around the floors. Rescuing a survivor by clearing a room of bioweapons and getting him/her to its entry point in one piece earns an extra life. Bombs are the most prominent item; they can blast through doors and destroy some hazards, making them a kind of a "get out of puzzle free" coupon.
The number of lives is limited. Losing one restarts the room if any are left, the floor if not. Saving is available, loading returns to the start of the floor.