Continuity: In several of the "summer" camp scenes it is clearly early spring. Many of the trees still have no leaves.
Revealing mistakes: The speed boat is racing in the lake at full speed. The shot cuts to the skiers POV looking at the boat and the pull rope is slack and there isn't any tension on the line at all.
Continuity: The water skier is doing his runs on the river. He is wearing a orange life jacket, but when he falls into the water the jacket is yellow.
Continuity: The position of the plane ticket in Earl's hand as he gives it to Maggie.
Continuity: As Dr. Hoak is attacked by a piranha, he gets onto a raft and his sweater alternates between torn and intact.
Continuity: The dressing that is on the evil Dr Leticia Baines's forehead keeps changing. When she is first placed on Grogan's raft, the dressing is soaked with blood. In the next few scenes it just has a small patch of blood in the center. After she swims to rescue the boy from his canoe, she gets on the raft and the dressing is dry. In the next two close-up shots the dressing is wet (with water) and then it is dry again.