Zombies are pretty fun if you don't play it 24/7.
There are only two maps (one of them is Nuketown and it's only available for Delux edition owners as far as Ik) but the other one is very nice too. It consists of 4 different locations and you can use a bus to transit between each of them. You also have to find some parts and upgrade (
) the bus, make zombie traps and so on but ts3/steam is VERY useful.
Nuketown is a bit easier and u'll get higher scores cuz it's not that big and u can always buy some very nice guns in the $950 random amo box (w/e u call it lol), you can't be left by your teammates in the other location, you can't fall out of the bus, you can always cover each other.
SP is also pretty fun. There are plenty of different drones, gunes and other stuff. You can change the end of the game. You can play for any unit (soldier and 3 types of drones) when u play the strike force missions (they don't have to complet them, but u better do so). There are also some other types of drones you can control in the main missions.
And MP is pretty fun too. I don't really like that they don't let players rent the servers but it's still good. It doesnt lag at all. There are maaany new fun game types like "One in the chamber" or "sticks and stones".
I say it deserves 9 stars out of 10.