Is it a single player game too or just multiplayer? Or is it like L4D: single player available, but kinda sucks and is only fun in multiplayer.
It has single and multiplayer. To be honest I prefer multiplayer if only because it's easier to have more people keeping an eye on what's happening and it gives you a better ease of access to destroying the monsters.
Though I play single player just as much if not more so I can work on leveling up my perk system and just have fun in general.