Other mistake: The plot of the film is that Annie Wilkes is angry with Paul for killing Misery in his book. As this is unpublished she gets Paul to burn this. The rest of the film Paul writes about Misery's resurrection. This would not be the case as she was alive and well in his last published book.
Other mistake: When Annie shoots the sheriff in the back, he fall forwards on the staircase where he stood. Annie walks down without moving around the corpse of the sheriff. She just advances forward as if he isn't there.