Revealing mistake: Just after Boog breaks the dam and the deer herd is bounding across the dry riverbed, at the moment they realize they are going to be swept downstream by the wall of water, their legs disappear - just left out of the animation cell. Very obvious; no slow-mo needed to see.
Open Season (2006)
1 revealing mistake - chronological order
Directed by: Anthony Stacchi, Jill Culton, Roger Allers
Starring: Martin Lawrence, Ashton Kutcher, Gary Sinise, Debra Messing
Continuity mistake: At the amphitheater, just as Boog chases Elliott through the curtain and off the stage, all of the items strewn about backstage that were there moments before (the paint can, the rope, the toolbox) are missing.
Reilly: Yo, O'Toole.
O'Toole: Yeah, boss?
Reilly: I want you to cantilever that cedar on a bias by the north side.
O'Toole: Huh?
Reilly: Put a twig in the hole.
O'Toole: Oh.
Reilly: Rookie.
More trivia for Open Season
Answer: I think after the flood from the dam happened, Boog lost his teddy bear. When he went to retrieve it from Shaw's house, he was soon driven to the cellar by Shaw. Shaw was also singing the lullaby because he had the bear. He must have found it, kept it, and listened to the song enough times that he memorised it.
Answer: Well obviously Beth sings it a lot, Boog goes to sleep to it. It also helps that Mr. Dinkleman plays the tune after you pull his string. It might be a popular lullaby in timberline.