Play in this new mode of RimWorld in which Zombies appear in the game. They are bad and merciless enemies. The increased difficulty will add much trill to the game. Remember that if the colonist is bitten by one of them, he slowly dies and then turns into a zombie. So, be alert and keep track of these nasty creatures and their origin. Do your best to avoid unexpected encounters with zombies and you will save your character and his counterparts. Enjoy!