Continuity mistake: At the lab, Freeze starts to laugh hysterically and raises both arms up to his face. A shot later, they're lowered at hip level.
Continuity mistake: After the cop has his keys stolen by Ivy, check the fingers on his hand leaning on the wall: they change position depending on the shot.
Continuity mistake: Ivy takes the keys from the cop and lowers her right hand. From a different angle, it's raised.
Continuity mistake: When Freeze freezes Frosty while he holds a newspaper, Frosty's position and the way the newspaper folds change between shots. The position and number of icicles around him also change drastically.
Audio problem: When the telescope is falling and the two people are with Batman, he tells them to grab onto his belt. The audio is terribly clipped.
Continuity mistake: While Bane is driving the limo, after Ivy puts on the wig, the gloves on her hands disappear.
Revealing mistake: At the gala, you can notice the stunt double driving the ice truck for Arnie.
Revealing mistake: In the museum, when Robin breaks the door with his bike you can notice that the door is made of foam rubber or similar.
Revealing mistake: When Batman is about to defrost Robin, he is holding a dummy.
Revealing mistake: While Ivy is fighting Batgirl you can see the stunt double replacing Uma Thurman.
Continuity mistake: Bane is pulling Robin and Batgirl but in the next shot he's pushing them.
Deliberate mistake: At the beginning when Batman and Robin are facing Freeze, Robin arrives and crashes through the wall with his motorcycle and leaves a shape in the wall that a motorcycle could possibly make. But, the next shot after Batman looks where Robin is still flying and about to land on his motorcycle, there is a huge bat shape in the broken wall. Obviously done for campy effect, but still a mistake regardless.
Chosen answer: Purely a creative decision, but based on the tone of this question I don't suppose you're honestly after an answer so much as you are just looking for someplace to express your distaste.
Phixius ★
Because Schumacher wanted to base the suits on Greek sculptures hence the nipples. Don't forget Robin's shorts or Batman wearing different colored cowls in the comics, perhaps this was a nod to that.
Rob245