Another lesser-known one I like a lot:
Happy Birthday to Me-Surprisingly long for an 80's slasher (About 110 minutes, with credits), it offers a nice whodunnit for the first half-until the killer is (Supposedly) revealed midway through the movie.
It does have a neat twist at the end, however even the writers admitted the reveal of who the killer REALLY is was added on at the last minute, as the original script had no twist at the end. Watching the movie, I'll admit it does feel a tad tacked on.
The motorcycle, weight lifting, and kabob kills were creative, though IMO the film's poster's promise (Six of the most bizarre murders you'll ever see) is not true, as though 3 are the only unique ones. Hilariously, the body count in the movie is 8 (Including the killer's death), so it's like they admitted "Hey, 2 of the kills aren't clever, but 6 of them are!"
Overall, I'd recommend it if you are a slasher movie fan.