Just got the game..some issues

[Mechanik]

It also bears mentioning that there are some movement tactics you should consider. Zombies do not always have to move (unless affected by Zombie Hunger). This means you can park zombies in certain places to block Hero objectives, or build up a mass of zombies somewhere safe (i.e. inside a building the survivors don't have line of sight into) before moving them out en mass to attack (and thus hopefully some of them make it to the Heroes without getting shot).

Just because thematically the zombies are mindless, doesn't mean you have to play a mindless strategy and just keep pouring single zombies into the meat grinder to get taken out with someone's revolver or the like.