I first saw this in the late 80s on a vhs.
Revisited it recently.
Donny keeps hearing his dead mother's dominating voices as the body of his mother is still kept in the house a la Psycho style.
Donny, inspite of being an introvert, somehow succeeds in picking up females n is able to lure them in his house.
Donny's house is a brilliant piece of location and adds an eerie sense.
Coming to the bad points, the movie is very slow. Nothing happens in the first 50 mins or so n most of the killings r offscreen.
The end too is a big meh.
What happens to the poor priest is never shown.
The movie has zero tension n zero suspense.
One can call it a poor man's version of Psycho n Deranged.