How do you level up in zombies?

#1TheAssassin27Posted 12/2/2012 8:44:36 PM
I've been stuck at the skull with blue eyes for a while
#2TheAssassin27(Topic Creator)Posted 12/2/2012 9:16:00 PM
#3areeb319Posted 12/2/2012 9:31:00 PM
Keep playing good, Get high scores/waves
I am L33T, well according to my karma I am
#4Admiral_XyesPosted 12/2/2012 9:33:04 PM
Essentially, "do well."

It's vague but I've heard doing things like buying doors, getting kills, getting headshots, and not getting downed contribute to your level. Also, it's based off multiple games so you have to be somewhat consistent.

My friend didn't get downed till wave 25 and he went from the brown shield w/ blue eyed skull to the green knife shield skull after that game.