Character mistake: As they take Han away, watch Lando. Just before he tilts his mask down so we can see who he is, he whacks his head on the doorway. (00:16:20)
Character mistake: When Richard Pryor is on the computer attempting to formulate Kryptonite to kill Superman, a screen shot of the computer shows the word "recieved." The I and E should be the other way around. (00:59:25)