I was was at troitskoe military base with enough gear for my friend and i when i aggroed some zombies, so i was gonna run to one of the barracks and close the door to shoot the zombies when i was hit multiple times by invisible zombies and killed. I have a xbox game clip to prove this. I almost uninstalled the game, i will not be playing for awhile that is for sure all of that work gearing up just to die to something i cant kikl.