Continuity mistake: Jason drags Vicky down the steps all bloody, yet doesn't leave any blood on the steps.
Continuity mistake: When Jason enters the cabin you can see an umbrella. Yet when Vicky comes in, she's using that same umbrella. (01:01:35 - 01:03:50)
Continuity mistake: When Jason comes smashing through the window at the end, to attack Ginny who is getting up from the cot, the camera angles are inconsistent with the attack. First he is lounging at her from behind, to grab her. Then his distorted face is suddenly at her left shoulder before he's even touched her Then she's looking back at him and screaming before his hands even touch her and pull her out of the window. (01:24:20)