Continuity mistake: When Lauren and Lara share cocaine in their dorm room, Lara's face starts out clean. After a few quick cuts between the girls, her nose is dusted with white powder. There is another quick cut to Lauren and back to Lara, and the powder is gone, before she has had a chance to wipe it off or move.
Continuity mistake: In the split screen scene, you can see the reflection in Sean's sunglasses of the window at the end of the hall. Since Lauren is standing in front of him at this point, this is an error. (00:36:29)
Continuity mistake: At the end, when Sean and Mitchell are in Rupert's kitchen, Rupert snorts some coke. Depending on the shot the coke either changes position or is not there at all.