Factual error: After Jimmy drops Cheddar off at the hospital after he shoots himself, Jimmy says that he hit an artery but he'll be all right. The artery would have been his femoral artery, and he would have bled to death in less than a minute.
Continuity mistake: When Rabbit and his mom's boyfriend were kicking each other's ass inside the Smith's trailer, Rabbit pushes or punches the boyfriend from the kitchen to the living room, breaking a small wooden post in a quick shot. A few shots later, when Rabbit returns to the trailer, the wooden post is intact. There was no time to fix it.