Pifias

(at around 42 mins) When Shack is talking to his teammate about the Everclear, you can see several people dancing at the rave in the background. But when Jason starts chasing him, they appear to be very far away in the cornfield.

(at around 42 mins) After Shack throws the alcohol onto Jason, it is a quick cut and all of a sudden he has the torch in his hand without even reaching for it.

(at around 12 mins) When Gibb goes to take a shower, Trey pulls the covers up to his chin. In the next shot when he reaches for a beer, the covers are down.

(at around 3 mins) 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.

(at around 43 mins) Jason was completely covered with white beer foam, but in the next shot he has no foam and his clothes appear relatively dry.

Freddy is shown knocking off the valve of a pressurized cylinder which will cause it to launch like a rocket. But pressurized tanks are never stored w/o the valve body protected by a screw-on cap. Fun scene, otherwise.

(at around 57 mins) When the drug "Hypnocil" is researched on the Internet, an article about the drug appears. If you read the article, you can see that it has nothing to do with Hypnocil. The article is about drug testing of students who engage in extracurricular activities.

Several times during the movie Freddy's sweater lifts up to reveal either normal, unburnt skin, or a tight black undershirt. For example, when Freddy is hanging upside down from the large construction vat (at around 1h 23 mins).

(at around 43 mins) Jason was on fire for a considerable amount of time, and yet when he is put out by the beer, his clothes appear to be undamaged and fully intact.

(at around 30 mins) When Freddy does the "Got your nose!" bit to Kia, you can see at the bottom of the screen where they cut off Freddy's glove in the computer when placing it in for the final shot (full frame only).

(at around 56 mins) When Lori is sleeping on Freeburg's couch and Freddy grabs her, the pinkie claw furthest from her bends like rubber.

(at around 8 mins) When Gibb says, "I am so under the limit, Lori", her lips don't match the line.

(at around 19 mins) In the second dream sequence, the goat bleats twice, but its mouth doesn't move.

(at around 19 mins) When Blake wakes up, he hears a noise in the bushes. As he walks towards them, we get a shot of the bushes moving - to the right of the bushes, the shadow of someone shaking them is visible.

(at around 16 mins) When Lori wakes up in the police station and follows the dropping blood, she turns a corner because she hears a little crying. Right after she turns the corner, the cameras show office windows. You can see someone sitting down and a camera on his knees.

In this film, it is revealed that Jason has a deep fear of water. However, in both Viernes 13: Capítulo final (1984) and Viernes 13. 7.ª parte: Sangre nueva (1988), he has no problem attacking characters from underneath water.

(at around 1h 14 mins) After the van crash, Kia sees a sign that says "Crystal Lake Resorts", but then they all walk in the opposite direction of it.

Deputy Stubbs tells the teenagers about his suspicions that Jason Voorhees is involved in the murders. Later the teenagers transport Jason to Crystal Lake to battle Freddy. If Crystal Lake isn't that far from Springwood, wouldn't the teenagers have already heard of Jason?

(at around 57 mins) When they are searching for Hypnocil on the Internet, we see a picture of the Hypnocil bottle reading "Hypnocil, 500mg, 1000 tab". We also see Hypnocil pills lying beside the bottle. Considering the size of the pills, the bottle could never contain 1000 pills. Not even close to 100 pills.