Revealing mistake: When the bus is being pursued, Smith steers it to trip several prepositioned explosives that blow up trees to block the road. In order to by pass a downed tree the Germans push a motorcycle around it, and you can plainly see that the tree was cut by a chainsaw. (02:18:40)
Continuity mistake: When Dave begins to disconnect HAL's circuits, one angle shows him unlock the first, second, then third unit. Just as he's about to remove the key from the third lock, the angle changes and he's pulling the key from the second lock and then goes for the third again. We know this is consecutive time as HAL is pleading with Dave the entire time. (01:51:45)