It is basically Borderlands but slower and with zombies. Co-op works alright, but it's turned on by default and most people don't realise and don't want to play co-op so you get kicked as soon as you join anyone. Microphone is on constantly too and one of the games I joined they were having a domestic so I ended up leaving that one.
Game is pretty buggy in places too, think it was a bit rushed and the player animations are at times odd or non existent.