Deliberate "mistake": In the scene where Boog and Elliot are raiding the convenience store, there is a shot of Elliot with his head inside a gumball machine. There's no room for his one good antler so the animators just "dead ended" it.

Other: When Shaw is on the ground near the end of the movie, a rabbit runs at him with a spoon. The spoon is facing inwards, yet Shaw's reflection is right-side up. (Slow motion may help.)

Continuity: This mistake occurs when Boog is in the hunter's house. The hunter returns, and Boog needs to hide. When he hides under the table, you see him duck under the table, and you see the hunter right next to the table in the next immediate shot with no time to get there. It is implied that the hunter didn't see Boog, but he can't be where he is standing in that shot without having seen the bear duck under the table.

Factual error: In the last part of the movie when the animals attack, one of the hunters call the warden. The hunter's phone is a SonyEricsson W710i. This phone does not support video calls and no camera on the LCD part of the phone where it fell forward and supposedly showed the videos to the sheriff.

Continuity: In the scene where Elliot is tied to the hood of the truck, Boog hears him making noise and looks over at him, and Elliot's tongue is hanging out of the side of his mouth. In the very next shot when we see Elliot from the front, his tongue is hanging out the other side.