The zombie tank is a bit stronger but very slow and cannot be knocked back
The zombie spider is an undead version of the normal spider
the zombie enderman the undead version of the normal enderman
The mod also adds new mobs one of which is the apocalyptic zombie
The zombie cow is an undead version of the normal cow
the world will change
The moon and the clouds also change
There are 2 new biomes, the wasteland biome is shown here
The 2nd biome is the desert wasteland biome