This one came out around the time of The Burning, which is among my favorite slasher films. I don't think there was ever a bigger year for the genre than '82. Madman has every ingredient it needs and absolutely nothing it doesn't. It's as basic as these kind of movies get.
The film opens on a spooky campfire story, which serves as the backstory for the ax-wielding psychopath. We've got a group of campers consisting of teens and small children. The children's plot armor will prove extraordinary even though, in real life, they would be the easiest victims to dispatch. The teens are played by adult actors, who will be easy pickin's for the titular madman. As usual we'll have to endure one plodding POV shot after another. As usual, the beater pickup truck will never, ever start when the characters need it to the most, and the most gratuitous scenes involve people ambling about the woods and cabins aimlessly.
The star of Madman is Gaylen Ross, who was also the star of Romero's Dawn of the Dead. She's more than adequate in the role, which isn't particularly demanding, but she looks uncomfortable appearing nude in an awkward sex scene. As soon as the sex is over, her boyfriend goes wandering the woods and gets himself killed. Naturally, another character goes looking for him and also gets killed—off screen, of course.
A little bit later, Ross's supposedly spunky friend pokes her head into a tent where two of their friends are getting freaky. It's a missed opportunity that the killer didn't separate her head from her body so that it could tumble into the tent onto her horny friends. In another scene, the killer is hot on the trail of a young woman who takes the time to empty the contents of a refrigerator so she can hide in it. The killer is so close when she does this, he's in the same shot... it's the worst attempt to hide ever.
It turns out there's a documentary about Madman. Early on, those involved admit the production was just a stepping stone to the art film they really wanted to make, which indicates just how lazy they were. How a documentary got made about this forgettable film, I'll never know.