Revealing mistake: In the dream sequence while Bruce is now the Hulk, if you look closely beneath his green wig, the black hair of the actor is visible.
Revealing mistake: When the Russians are in the Finn's trench, you see the Finns stabbing the Russians. If you look carefully, on a few of the Russians you can see protection visible. (00:48:45)
Revealing mistake: In the fight scene in the Alley you can tell in all the shots from behind they woman is a much younger and smaller stunt double. (00:22:30)