A single-player campaign, only you, your super shotgun, and almost no enough ammunition to kill every demonic on Mars. It feels like a Doom game, because you are desperately trying to find a healthy pickup to keep you moving forward. This is a growing demon animal. It's exhausting, exciting and a bit stupid, and when you get into it, you'll walk along. In the worst case, Doom is a series of repetitive closed rooms, full of demons, you have to kill all of this to advance, complemented by derivation and well thought out multiplayer mode.