hmm well with 3 people get good guns nd upgrade them of corse nd 2 go in front the entrance of the cave nd they take care of it nd 1 cover down. And in one of my games, it was me cover the window in the cave. GUT SHOT (a.k.a the trench gun) PWNS!!!! and the ray gun
and with 4 people if ur lucky 3 people cover the front 1 in the cave but 1 person should be goin back and forth back and forth nd so on so he/she could help both. Cuz trust me at lvl 26 zombies came in like crazy in the cave but the trench gun killed like 17 of them in 1 shot!!! amazing shot