Continuity mistake: When Michael is doing his bike up and is spraying the cycle's gas tank, his hands are full of oil, but in between his fingers are clean. This shows that is is obvious someone has smeared the oil on, otherwise in between his fingers would be just as dirty. And his hands wouldn't be perfectly black, they would be streaked.
Continuity mistake: In the scene at the end when Johnny gets out of the raft, you see him walking up through the back of the crowd and in the next shot, he is throwing his costume off his back on the side of the pool, then cuts back to him coming between Michael and Stephanie.
Continuity mistake: The scene when Michael is jumping over the cop car and it cuts to a front shot of the jump, you can see Stephanie, Paulette and Rhonda watching him jump in the background, even though Rhonda had walked back inside the bowling alley with Goose and Davy before Michael reappeared from the chase.