Continuity mistake: When Squints is at the pool, his hair goes from flat down to sticking up, espically when he kisses Wendy.
Continuity mistake: When the gang are jumping into the pool (minus Ham) there is a life guard watching the shallow end - in one shot he is leaning foward but when Ham says "Oh sexy" he is sitting up straight.
Audio problem: When Yeah-Yeah goes over the fence, he's panting but his breathing doesn't match his mouth or shoulder movements.
Revealing mistake: When Benny jumps off the fence, it's obvious it's a stunt person doing it instead.
Continuity mistake: When Wendy sees that Squints is drowning she takes her sunglasses and whistle and throws them off the tower, but when she gets back on her tower after kicking the boys out they are back.
Continuity mistake: When Wendy is giving mouth to mouth to Squints her head is next to his chin, but when we cut back to her she is now 5 inches away from it. Her hair also moves from the left to the right. (00:37:00)
Factual error: At the beginning of the carnival scene, the Gravitron ride is in the far background. This movie is set in 1962, and the Gravitron was not introduced until 1983.
Continuity mistake: During one attempt to retrieve the ball, the boys use a pot attached to a long piece of angle iron. When they flip the whole contraption over to grab the ball, the part of angle iron outside the fence is still facing in the original direction.