गूफ़

When Harley and Nightwing have their big fight, Harley uses a little bit of Joker venom on her ring to hit Nightwing and causes him to start laughing himself into unconsciousness. There is only one problem with this, he is never hit anywhere near his face during the entire fight, and the joker venom should have been completely useless, as the rest of him is completely covered by his suit.

Captain Clown from The Last Laugh (1992) couldn't be there because he was a robot who was destroyed in that episode. But one should note that this is not a direct sequel to Batman the Animated Series and has yet to be confirmed as part of the DCAU.

After Nightwing is hit in the face, he starts to laugh and his face gets all weird looking. The problem is you can see the were the animators put the smile over his face, and it was clearly painted over his real one, to create the laugh.

When the cars are stopped on the highway so the police can search them, the highway signs are facing the wrong direction corresponding with the traffic flow.

Harley is seen working at Super babes, but doesn't seem to be concerned about showing up for work. Not only was this her only job, She was also hiding out from the law there. So, after her big adventure with Nightwing and Batman, did she ever go to work again??? Not only would she have no cash, but her boss could have turned her into the authorities at anytime. The film doesn't bother to answer this question and just leaves it oblivious.

How does Nightwing get hit by Harley's Ring??? This film follows the comics, and Nightwing has a very athletic fighting style which is hard to counter, so he should have been hit much less and shouldn't have fell for such a simple trick but yet he does. This is not explained and is glossed over.