Other mistake: When encased in rock, George lights a match to see the current time dial on his machine. But the dial is backlit every other time its shown.
Other mistake: When the character plays the guitar throughout the movie, there are obviously no strings attached to the guitar.
Other mistake: Near the end of the movie, when an Air Force sergeant is looking at the airfield through binoculars, the binoculars are up against his forehead, not his eyes. (01:23:00)