Continuity mistake: When Indy and Helena find the antikythera in Archimedes' tomb, it's covered in dust and no features are visible. When Indy reaches for it, it's just slightly dusty.
Continuity mistake: When Indy is shot, he falls with the strap of his satchel running down the side of his body. A shot later, he lies with the strap running across his chest. Then, a shot later, the strap is nowhere to be seen.
Revealing mistake: When the AA machinegun on the train goes berserk and destroys everything, Indy hides behind some crates. For several shots, Harrison Ford is replaced by a lame CGI, which transforms his head into a videogamish, lifeless face.
Revealing mistake: When young Indy jumps from his car to the motorbike and fights against a German - and the following scene where he rides on the bike towards the train - his body and especially his face are a blatant CGI creation with unnatural movements, dead eyes, and waxy, lifeless expressions (most noticeable in theater screenings). (00:05:53)
Continuity mistake: A woman is shot at at the college and lies down with her right leg bent. A man tries to move her but is killed before he does. The shot changes and her right leg has swapped to lying straight.
Continuity mistake: During the parade, a red convertible skids and stops in front of Indy. Shot changes and it's skidding and stopping again.