Critique:
Wall side: Good!
Wall top: Good, but the seam shows a bit (problem on the northern edge)
Doors: Good! I really like them.
Zombie: Good, but I'd prefer it with eyes.
Players: All good, especially the one with a shotgun
Floor: So far, NH floor looks better. The alt floor makes the whole picture too gray. You should have showed us how does the third alt floor look too.
Overall: Very nice! I like them!