Zombie character not appearing in multiplayer

[Dekoyski]

Has anyine ever unlocked it? Finished all the tiers,and finished the cut scene still no character zombie in multiplayer... Help pls?

 

[Grim]

From what I can tell, you just need to keep playing the level ("riot") in order to unlock all of the armor, and eventually the zombie character.

That's what I did, and I never really did anything different than survived and then escaped.