Continuity mistake: When the Mini-Ashes have Ash tied up and are holding his nose shut (so he'll open his mouth), when the scene briefly cuts to a POV shot from the one Mini-Ash that's performing the dive into Ash's mouth, the other two now suddenly have switched to holding Ash's mouth open with their hands, then immediately the scene cuts back to Ash opening his mouth (again) and the two Mini-Ashes are now holding his nose shut.
Continuity mistake: Ash is chased by an evil entity to an abandoned windmill and only prevents it from getting him by barricading the door shut, yet when he smashes the mirror you can see the door behind him and it's wide open. (00:30:10 - 00:31:45)
Continuity mistake: When Lord Arthur shoots the crossbow at the fleeing prisoner near the beginning, the camera angle changes to that of the arrow. For a moment, before the camera changes angles again, the arrow is going slower than the guy running. (00:10:30)
Answer: Towards the end of the film, when Ash mounts his horse and rides off into the sunset (before it then cuts to present day and he's back at the S-Mart), you can see his chainsaw is strapped to the horse's saddle. It seems that he either recovered it after the battle or perhaps he sent someone to the windmill to retrieve it.