Another bad one was My Bloody Valentine, a 70s? Canadian film about a mine where some guy had killed his co-workers. So the mine got shut down and 20 years later some kids who go down in the mine overnight to celebrate Valentines Day get killed by this guy Harry Morden who has been living in the mine all these years.
Of course they get killed in various ridiculous ways using mining equipment(that is still there and still is fully functional).
Even after discovering their friends mutilated bodies and a heart boiling in the kitchen in a big pot on the stove (never knew mines had kitchens with full gas stoves underground). some of them even stop while trying to escape, to of course have sex, but get killed as well.
Terrible plot, terrible acting, bad lighting, it had it all.