A group of forensic science undergrad students go to a remote island with their instructor. On this "Body Farm" corpses have been placed and the students, as a test, have to figure out how long they've been dead and what they died of. There's a slight complication, though. The island was formerly used for biological experiments on prisoners, experiments which cause the dead to resurrect...
13 EERIE is a surprisingly effective zombie movie, with gooey, Fulci-esque zombies (there's even an eye gouging), extremely grim. Highly recommended.