Factual error: When Ash finds the bridge destroyed, in a side view we see the bridge missing, and both cliff edges either side of the screen. However the right cliff side is up MUCH higher than the cliff Ash is on. (00:10:45)
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)
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: 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.
Answer: Sam Rami could not get the footage of Evil Dead to use in the sequel, so he remade the movie in a shortened form for the beginning. Since Linda was the only original character other than Ash to come back he included her in the recap but deleted the others as not to waste time. An in universe answer could be that trauma of losing his friends made Ash block them out and rewrite history in his head, except for Linda who comes back to haunt him in the movie so he is forced to deal with it.