Revealing mistake: When Barry stands at his uncle's dinner table to supposedly "toast" Captain John Quinn for his pending marriage, to Barry's cousin Nora Brady (who Barry is in love with), he throws his glass in Captain Quinn's face instead. However, the glass noticeably breaks before Barry even throws it.
Revealing mistake: Establishing shots of the party where Chaney will fight Pettibon's guy; when we see the band play and people dance, the footage is rather obviously stopped and reversed to give the impression of a longer shot (evidently they had too little usable film of the crowd dancing). (00:31:00)
Revealing mistake: When the black guy is attacked after being let go, his throat is slashed. Check out how dreadfully fake the blood is. It looks like watered down ketchup.
Revealing mistake: When Tim crashes the van into Jill's mini when she is reversing into a parking space, the rear light on Jill's mini is already broken before the van hit her car.