Character mistake: One of the top most taboo things for a super hero to do is reveal any aspect of another hero's identity to someone, especially a villain. But when Flash is trapped by the gray adhesive and the other Justice League members are about to take the villains away to disarm the bombs, Flash tells Green Lantern "Hal, go", calling Green Lantern by his first name right in front of Mirror Master. (00:08:05)
Character mistake: As the movie begins, a book opens up with various fairy tell things written in it. The name Cinderella is misspelled "Cincerella" on the second page, but is spelled correctly on the first page. It is also apparent that the second page just has some of the same text as on the first page. (00:00:20)
Character mistake: When Barb introduces herself to Flint, Steve calls her a monkey, and she corrects him saying that she's an "Orangutang", pronouncing the G at the end. But the correct word is Orangutan, with no G sound. Barb would surely know this, as a genius ape.