Plot hole: At the angle of descent and the speed it was traveling (still burning from reentry even), when the space shuttle crashed in the opening of the film, it would not have left much of anything behind. The kinetic explosion that would have resulted would have downed the forest around it for a good distance leaving a crater, and the clean up crews would have been lucky to find any piece of the ship itself still intact bigger than a football. Much less been able to find any discernible remains of the crew. Yet bodies were being taken out in still relatively good condition. And probably most unbelievable is that the glass containers holding the Symbiotes were not even broken.Quantom X
Plot hole: As the evolved Predator's ship takes off it leaves Casey Bracket alone in hilly forest terrain. The ship then flies a long distance before crashing and the Predator and McKenna start fighting, just for Bracket to show up and help out of nowhere. Impossible for her to cover that distance that fast in hilly forest terrain.
Plot hole: Max, an intelligent zombie, gets into the air duct system and is crawling around above peoples' heads. This is an aluminum metal tube with open vents and he's a clumsy, untrained zombie. He climbs over peoples' heads in the vents banging the metal but nobody ever hears him. When Zoe and Baca kiss in the hallway, he even growls in anger and shifts around, not even 10 feet away from them growling through an open vent. Yet nobody ever hears him, until its convenient for the plot later and a guy thinks it's rats. (00:41:30)Quantom X