Deliberate mistake: When the people come into the club looking for money off the owner a fight breaks out between the Krays and the people the Krays stick a sword through the gang leaders hand. But it quite obviously goes through the gap in his fingers. (00:35:10)
Deliberate mistake: In the whole of the 'Psycho' series, there has never been a closet door next to the dress cabinet in Mother's room, but for this movie there is suddenly a closet.
Deliberate mistake: After Ryan and Michelle finish changing the flat tire and are surprised by Leatherface, he chases Ryan around the back of the car and smashes the windshield. At the moment the camera is in the backseat shooting out, we see the chainsaw with the chain popped off and hanging. My best guess is that it was done intentionally (for safety reasons) because the saw was close to Ryan. The crew must've been too lazy to completely remove the chain and just popped it off the track instead. (00:25:25)
Deliberate mistake: When Casey is hiding behind the boxes waiting to knock out a Foot soldier and steal his outfit, you can see he is still wearing his denim vest. After he knocks out the Foot soldier, he is able to put on his entire outfit in roughly three seconds. (01:10:15)