The zombies is really good and is the lasting legacy of this game. Official maps are great as long as you can get past how cryptic everything is (youtube tutorials are your friend), and the custom maps through the Steam Workshop are a huge plus. The campaign is bad even by COD campaign standards. The multiplayer offering isn't great either, the movement abilities all feel clunky and the maps barely take advantage of it. I'll keep playing it for zombies and nothing else.