Revealing: When Robin is being pulled underwater by Ivy's plants he surfaces for air and gets pulled under again. It's obvious the film was just rewound. Then when he finaly gets free we see the shot that was rewound was the same shot used when he escapes. Really bad editing.

Continuity: When Robin steps foot into Poison Ivy's lair she is laid out on her flower bed. If you look at the sleeves of her costume, the ends of the sleeves are fringed in a simple leaf like design. Robin spurns Poison Ivy's affections, and an enfuriated Ivy pushes him into the lily pad pool. She is then confronted by Batman, and a soon to arrive Batgirl. Now - look at the huge, obvious, black rubber "thorn" bracelets that suddenly appear on each of her wrists.

Revealing: When Freeze is freezing the town, the cop car that crashed into the store has flexible icicles on the driver side door. Also when the city is being defrosted, when the cop comes out of the car, the icicles are very wobbly.

Other: When Mr. Freeze threatens to freeze all of Gotham City, he has a big snowglobe in his hand. He freezes the snowglobe, then shatters it in is hand. When he crushes it open with his hand, the inside of the snowglobe is empty. There is no water, frozen or unfrozen, that comes out of the snowglobe when it breaks.

Revealing: After Arnie freezes Robin, then freezes the doorway, then wipes his hand on the ice to wave goodbye to our hero, you can see that the clear spot is there before he wipes it with his hand.

Other: Apparently, guessing Alfred's password also turns computer monitors into projectors. Before Barbara guesses the password, none of the light/information on the monitor reflects off her, but afterwards, she might as well be a projector screen.

Continuity: When Poison Ivy is talking to herself when she is leaving the observatory, you can notice that the policemen she pushed away have vanished in the backround.