Revealing mistake: In the final 1/2 hour there's a scene in which Kevin Bacon is drifting weightlessly in the lunar module, with a roll of duct tape floating nearby. Just during the last couple of seconds of this shot, suddenly he & the roll accelerate to the right. As everyone now knows the zero-g scenes were photographed on-board an aircraft which flies free-fall arcs for up to about 20 seconds before having to level off. The sudden acceleration on the set means that shot was filmed just as the plane was leveling off from a dive.
Revealing mistake: As Jim Lovell looks down on Fra Mauro and has a dream about an EVA (walk) on the moon, we soon see a view of Jim's legs as he jumps from the Lunar Module ladder down to the lunar surface. If you look closely, just as his left leg flings backwards from the ladder, you can see that not only do his pants appear to be a cheap replica of the actual Apollo space suit, his ankle (with bare flesh) is visible just under. If your body were exposed to the vacuum of the moon, you'd be killed.