Revealing mistake: When the kids step out of the water and walk towards the house, the floor is already soaking wet from previous takes.
Revealing mistake: When Leslie is fighting the soldiers, one soldier hits a second soldier with his rifle. The rifle can be seen to bend around the soldier's body and then straighten again. (02:12:10)
Revealing mistake: Near the beginning of the film, when Clang is outside the Beatles' flat on his delivery bike, you can plainly see the rope tied to the front of it giving him a pull as he starts to ride off. In the next shot the rope is gone.