Form - Lots of gloriously atmospheric shots. My favorites are when the zombies mystically teleport in and out of shots. The copious amounts of fog also help.
F/X - Not as good as The Beyond, although it definitely has a nice bag of tricks. Drills through the face, spitting up random flesh and organs, etc.
Acting - Everyone just talks like they're scared the whole movie, which makes sense to me. Teleporting zombies are scary as hell.
Mise en scene - Good. The placement of the maggots in the maggot wind sequence are phenomenal.
Quotables - They talk a lot about the Book of Enoch if you're into that sort of thing.
Cool stuff - The soundtrack is absolutely phenomenal, and the gruesome scenes are all on point. No silly spider sequences from the Beyond, no obnoxious bat squealing death from House by the Cemetery. I get sucked into this film like no other Fulci film because it manages to never break the atmosphere. Easily my favorite Fulci.