If you're willing to get over the extremely implausible scenario presented by this movie where young Jason Voorhees never actually drowned, lived alone in the wilderness for 20 years without anybody finding him, including his loving mother whom he apparently witnessed being beheaded at the end of the first film, you'll find a better than average, engaging and effective slasher flick that I judge to be one of the better movies in the series. Friday 2 takes every good idea that the original had and builds upon them, while killing off many ties it had to its predecesor (sometimes literally).
Our killer is set up as a campfire legend by a group of camp counselors in training. After one of the teens wanders too far in his territory, the realer than expected, deranged and vengeful Jason begins picking the intruders apart one by one in the series' trademark fashion. Amongst this group is aspiring child psychologist Ginny Field, our "last girl" and one of the few characters in the franchise who delves into Jason's psyche and actually stop him in his tracks.
The atmosphere is suspenseful, the script and acting are better than you'd expect from a Friday film, the kills are great (and apparently ripped off from Italian horror movies) and it all leads up to an intense climax that stands as one of the series' best. If you like shlock, this is a very well made piece of it that holds a couple of good surprises.