At the start of the film, in the course of a single motorcycle ride, Vanilla Ice's haircut changes completely.
When Kathy gets back on her horse, her reflection on Johnny's glasses shows her sitting on the fence and not actually riding the horse.
After the motorcycle ride, Kathy asks Johnny, "Where are you from" without moving her mouth.
When Johnny steps out from Kathy's room, climbs through the window, and the lawn sprinklers start working, he jumps over camera rails.
When Johnny first picks up Kat from her house, where she has lived all of her life, she very briefly tries to push the front gate instead of pulling it.