Revealing mistake: Ash faces the oval, wall-mounted mirror and tries to reassure himself that he's fine, until his mirror-image lunges out and tries to strangle him. Throughout this scene, the background set and lighting "reflected" in the mirror changes very noticeably between the real mirror and the hole-in-the-wall practical effect. Additionally, the Ash that lunges through the mirror is NOT a "mirror-image" of the other Ash, as the blood patterns on their faces are distinctly different, which is obvious in the face-to-face profile shot. For that matter, the blood patterns on Ash's face are inconsistent all throughout the film, frequently from one shot to the next.
Revealing mistake: When Evil Ed tears off some of Bobby Jo's hair and eats it, the head is made out of latex (Watch for how easily everything bends on his face, even the jawbone bends at one point).
Other mistake: When Ash decapitates Henrietta with the chainsaw at the end, watch very closely: her head comes off about five centimetres BELOW where Ash hits her.
Revealing mistake: When Ash stomps the trapdoor onto Henrietta's head and her eye flies out, the closeup reveals that the "eye" is something like a styrofoam ball with the veins painted on.
Chosen answer: Evil Dead II starts out with a recap of The Evil Dead where Ash cuts off the head of his girlfriend Linda with a shovel and then is attacked by the entity, which is how the first film ended. While Linda is played by a different actress, it's still meant to be the same events as The Evil Dead. The cabin windows are still barricaded from the end of the first Evil Dead, and Ash's pant leg is still torn from Deadite Scott attacking Ash. Additionally, the end credits say: "Evil Dead II", the sequel to the ultimate experience in grueling horror, was filmed in Wadesboro, North Carolina and Detroit, U.S.A.
Bishop73