When Hobbes shoots the school teacher, after he fires one shot, his gun is apparently empty (the action on any semi-automatic 9mm handgun, like Hobbes' Glock, stays open when the final round is expended, as can be seen in the two quick cuts after the shot is fired). However, when Hobbes approaches the body in each view after-wards, the action of the gun is closed, indicating that he still has ammunition.
After shooting a man on the street, Hobbes walks over to the man lying in the street. The dead man is shown with a gun still in his hand, but when Hobbes reaches only the man's feet (nowhere near his hand), Hobbes is seen kicking the gun away.
When Hobbes returns to the wood cabin towards the end of the film, he enters and stands looking around for a moment, with a window to his left. A definite human shadow can be seen walking past the window, despite Hobbes supposed to being alone.
As Hobbes is driving up to the cabin in the woods, what looks like a cat dashes underneath the house into what appears to be a crawlspace of the type found under houses built on piers. Yet later, Hobbes goes downstairs into what looks like a full basement. Houses on piers do not have basements. The cat runs under the fuel oil tank, not under the house.