Other mistake: The drip-meter that is supposed to administer Jigsaw's medication is not turned on. Anyone who has spent time in a hospital and seen one for real knows that a lot of numbers are shown on the displays when it is running to show medication status. (00:13:50)
Suggested correction: It's not specifically stated that the machine is in use. That's just an assumption. It could be set dressing he's using to enhance the perception of his condition.
Continuity mistake: In the part right before the girl is thrown in the heroin needle pit, Jonas takes the envelope with the drug dealers tape. When the cop's son pulls the cover off the pit, you can see that the envelope that Jonas just ripped off is still on. It's right near the bottom of the screen, and in the middle. (00:49:30)