Continuity mistake: In the scene right before "cool" when the two girls are crying, when they enter the garage their clothes are different.
Continuity mistake: In the "Dance at the Gym" scene, while everyone is doing a pelvic swivel with their partners, Riffs arm is around Graziella's waist. In the next shot, his arm is down. (00:32:30)
Continuity mistake: In the prologue of the movie, two guys on the Sharks throw yellow paint on Baby John, Arab, Action, and Snowboy. When they are talking to Lt. Shrank and Officer Krupke, they are all clean, but wearing the same clothes as earlier. (00:13:05)