It's still a good suspenseful zombie flick but there were too many stupid things like girlfriend upset with boyfriend for killing an infected person. Guys running into buildings full of zombies for unexplained reasons. Brimstone Protocol designed to contain the infection? They're on an island for god's sakes... The only protocol to ensure containment is to quarantine the island and all from there.
The revelation about the zombies near the end is definitely cool though.