You start the game in an elevator and must retrieve the passcode to get to the next level. You must explore the floor you are on and find the hidden passcode, all while fighting robots and turrets. There are three weapons; pistol, shotgun, and rifle, all of which have an alternative fire mode. There are health packs, ammunition, flashlight batteries, and powerups scattered throughout the levels for you to pick up.
Each floor is randomly generated, so every floor, on every playthrough, will be different.