Continuity mistake: When Ash is in the pit and the spiked walls start moving inwards, how far apart the walls are keeps changing but not in a logical order until he crawls out of the pit.
Continuity mistake: Ash's hairstyle varies throughout the film. The scene where he get the Necronomicon is the most obvious because in that scene he has very bushy hair.
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.
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.