Other mistake: While Nisi and Mickey are in the kitchen, when Isaac and Manley walk in, on the counter is a box of instant grits with tape covering its brand name (Quaker) and a bit of tape covering the face of the company logo. Then when Mr. Blakemore takes out the ice cream there's tape covering its brand name as well.Super Grover
Other mistake: In the scene where Ripley throws the basketball at Johner, Christie says to Ripley, "Ok, I've got a new game, tag .." He hits her with the handles straight in the face once, he misses the next shot, misses again, and Ripley hits him to the ground, but you neither see or hear the handles fall. (00:23:15)
Other mistake: While fighting Mr. Freeze (and Bane) at the Gotham Observatory, Batman, Robin & Batgirl all have batsuits on, with silver bat (or robin) symbols on their chest. But while they are giving Alfred the cure to Stage 1 of McGregor's Syndrome, for some reason they have changed clothes before giving him the cure. Because now (other than the fact that they have all taken off their masks) Robin has on his original robin suit (with the red robin symbol across his chest) and Batgirl has on a gray t-shirt. (01:55:25 - 01:56:15)
Other mistake: The first time Rachel brings the team coffee, she has six coffees on a tray. There's five cappuccinos and one regular coffee for Harry. On the tray there is five coffees on one side and one coffee at the other side, obviously being Harry's regular coffee, so that Rachel would be able to tell the them apart. But when she gives Harry a coffee, she gives him one of the five standing together, so he obviously got one of the cappuccinos.