Wait till the Zombies get through the barrier, then kill them. at the end of the round rebuild the barrier. it should give you 10 points for rebuilding the barrier.
You hack it
It does have a zombie mode and it is really fun.
(sadly) there is no zombie mode in CoD 4. the only zombie modes (so far) is the sombie mode in world at war and the zombie mode in black ops.
No
Yes, there is.
Yes
no
Yes
five
there is no other cooperative mode, only zombies
Yes it has a Zombie Mode and 3 different Zombie maps
Black Ops