Continuity mistake: When Mark says "The parents burned him alive" you see Lori lifting her hand to her head. When it cuts her hand is gone. (00:27:05)
Continuity mistake: In the scene where Linderman and the deputy is watching Freeburg throwing all the Hypnocil pills down the drain, they are looking through a glass. Then you see Jason coming up from behind lifting his left arm with the machete reflected in the window. When it cuts he lifts his arm again but this time it is his right arm. (00:59:05)
Continuity mistake: In the opening sequence, when Heather (Skinny-Dipping Girl) runs down the pier, the first overhead lamp sways violently back and forth. However, in the next shot a second later the lamp is dead still. (00:03:00)
Continuity mistake: When Will says "Let's tie the bitch up" you see Kia lifting her hand up. When it cuts her hand is down. (00:53:55)
Continuity mistake: Linderman accidentally shoots a Glock 17 in the van, grazing Will's right ear who grabs it, but during the remainder of the film there isn't a graze on his ear at all.
Chosen answer: Jason survived due to his unique healing abilities, at the end of the original "Friday the 13th" he is shown coming out of the lake. He is deformed with some mental handicap.
MasterOfAll