When someone wants to lock someone else in the basement, the lock is on the outside of the door. Later, when someone wants to lock someone else out of the basement, the lock is on the inside of the door.
When sister stabs brother in his left eye, it jumps over to the right eye in the next scene, then back to the left eye again.
When Sarah is in the car, looking out the back window you see the highway and a few cars driving along. When she is outside talking to Kyle, if you look back along the path they had driven up on, you see it looks like a long dark trail with no light and appears to go off into a fair distance.
When the woman extract the bullet inside the guys abdomen using a set of pliers, the bullet comes out sideways rather than ''bottom side out first"