Revealing mistake: When Jason cuts off Freddy's arm you can see the actor has his arm tucked behind him under his sweater.
Revealing mistake: When Freddy drops the large boiler on top of Jason during their fight in the warehouse, the boiler is made of cardboard or some other lightweight material because it doesn't land very hard and it even bounces a bit.
Suggested correction: It is also a dream which means anything can happen.
Freddy was trying to kill Jason. Why would he drop something on top of Jason that was too light to crush him?
Revealing mistake: When Jason swings his machete at Blake on the porch, as he swings you can see the actor stop swinging so it doesn't even make contact with Blake at all.