i thought the zombies were supposed to increase in level every week, i have been on the front every time and i have not seen any changes in difficulty levels
They do but it's depending on if you beat the ones in that territory from the week before.
Level 30 places:
Week 1: Stingy Zombie - Defeated-
Week 2: Earthsplitter Zombie - Defeated
Then it will follow how Earthsplitter zones go.
Level 60 Places:
Week 1: Earthsplitter Zombie -Defeated-
Week 2: Phantom Zombie -Defeated-
Week 3: Stygian Zombie - Defeaated-
If you have done the above for the 3 weeks it's been out then the next week you'll be on Week 4's
Lvl 30 Place
Week 4: Stygian Zombie
Lvl 60 Place
Week 4: Beast Tamer Zombie.
Not sure if it's beast tamer since that's for Sunday's week. But we'll see going by the pattern of the boss jumps Beast Tamer should be the one after Stygian.