Factual error: In the "Groovy" shed scene, Ash holds a double-barreled shotgun in one hand and saws through the gun barrels with his newly-mounted chainsaw in about 2 seconds flat. He could no more cut through a hardened steel shotgun barrel with a chainsaw than he could cut through a marble counter-top with a butter knife.
Factual error: As Ash is hunting his rebellious hand, he blows a hole about the size of a fist in the wall, then removes two spent shells from the shotgun. At that range, a double-barreled shotgun blast would have dealt much more damage. At several later points, he deals the exact same damage to a wall with only one barrel. (00:32:45)
Factual error: A line of blood flies onto the door of the work shed while Ash is using the chainsaw on Linda's head. However, the shadows of Ash and the head show that they are perpendicular to the door. All of the blood would be moved by the chainsaw in the direction of the cut, either toward Ash or the wall behind the head, so there is no way that much blood could land on the door. (00:22:00)