I see your Madman and raise you one Satan's Blade, The Nail Gun Massacre, Don't Go in the Woods, Pieces, The Mutilator, or Blood Rage. I'm not talking personal enjoyment here. If we're going to use a term such as "one of the worst ever," we have to aim for a modicum of objectivity and look at the craftsmanship the film. I.e. cinematography, acting, writing (plot curve, internal logic, etc.), editing, production values, etc. Madman has better cinematography than most of the titles I just mentioned. The acting is all over the place, but that is also the case with fan favourites such as The Mutilator and Blood Rage (I don't care that it's Louise Lasser, she misses believability by more than a few hairs in her disastrous 911 call). I've sat through much of Alien Beasts (you can find it on Youtube), btw. It's not a slasher, but I am confident that technically, this is the worst movie I have ever seen (and quite unenjoyable to boot). I'm not kidding - this movie really puts things into perspective.