Continuity mistake: Towards the end of the movie Dave takes Walley's jacket and uses it to help them slide down a cable. Before they slid down, Dave tells Walley to hold on, and Walley asks if they're going to be above the ground. Dave tells him no, and off they go. However, Dave is deaf, and reads lips, and Walley is standing behind him when he asks the question. So how did Dave read his lips if he wasn't looking at him?
Revealing mistake: When Dave and Walley are running with a car, Walley says that he heard some shots. Dave replies that he didn't hear anything, but as you know Dave is deaf, and he reads Walley's lips each time he speaks. In this scene, he wasn't looking at him, but answered. (00:47:45)