During the D.E.B.S. first stake out of Lucy when they are hanging over Lucy's head, Max is sitting next to Sara. After the three girl's swings move off then come back to Sara, Janet is sitting next to Sara. It would have been difficult for Sara and Max to have switched places hanging that high in the air.
When Lucy drives Amy, Janet, and Scud through the off-limits tunnel to the club, just as the car approaches the skull image, we see Lucy at the wheel with bare shoulders. During the rest of the drive, she's wearing a long-sleeve black shirt.
When Ninotchka calls the DEBS house to inform them where Amy is, the phone that is ringing and wakes Max up, is different (as is the ring itself), than the phone Max picks up. Angela Robinson acknowledges the goof in the commentary.
When the DEBS are approaching The Bank, they are told that it is coming up on their left and we are shown a "navigation screen" verifying this. However, when they actually pull up to The Bank, it is on their right.
When the DEBS are trapped in the vault Max is seen banging against the vault door with a lead pipe. After another scene with Lucy and Amy, we see the remaining DEBS crouching down as the spikes come down and you see Max with an even longer lead pipe. Where did they get a lead pipe, much less two of them in a bank vault?
During the scene at N-Game before chaos ensues, Lucy is spotted by a boy cleaning his teeth in a doorway. When he runs out to shout that he saw Lucy Diamond he is carrying a joint between his fingers. It is acknowledged in the commentary that he was supposed to be originally smoking pot in the scene, but it was changed for the end product.
When Amy and Lucy bump into each other the first time, pay attention to Amy's hands. The close up of her picking up the gun shows her using her left hand, but in the next shot she's holding the gun with her right hand.