When Russell gives Tommy the videos the doors to the room open out, but later when Peanut is followed by Monica and is let in the room with Tommy, the doors open in.
Near the end of the film, Frank prepares to stab Monica but shoves the knife into the ceiling, releasing a pile of white asbestos dust all over himself. A moment later he falls from the balcony but when we see him on the ground, there is no powder on him at all. Then a close up shot shows him spitting powder from his mouth, and there is some on his head.
Frank's rubber gloves appear and disappear.
The cars passing by the bus don't match up between shots of the bus driver and Tommy on the intercom.
When Tommy auditions as the Cream Machine, he pours two containers of milk all over his body. In the next shot, when he is leaning over a table, his back and legs are dry.
In LA County courts the defendant is always in regular clothes and not visibly restrained in front of a sitting jury.
When Tom is in the jail cell with Carl, Tom calls Carl "CBW", but his full name is Carl Wayne Bishop (CWB).