The core gameplay of pkz is the same as psycho killer. The game ends when the fifth psycho killer is drawn, and the winner is the player with the fewest points in their injury pile.
the NEW SELFISH, POWER, healing AND PREDICAMENT CARDS ARE PLAYED JUST LIKE the ONES IN the BASE GAME... BUT now there are zombies!
When a psycho killer or a betrayal is played, you do not have to play zombie weapon cards INTO YOUR INJURY PILE.
instead, you only play them if you become infected!
You become infected if you have an infection card in your hand.
If at any point you are holding a zombie weapon and an infection card, you must play the zombie weapon into your injury pile immediately - with no exceptions.