Some personal favorites not mentioned...
. Fulci's City of the Living Dead aka the GATES of HELL (1980)
.MOTHER'S DAY (1980) If you haven't seen it...you should. Not what you would expect!
.COMBAT SHOCK (1984) Depressing? Yes. Horrofiying? Defintly! I CANNOT RECOMMEND THIS MOVIE ENOUGH!!!! aka American Nightmare
.Argento's PHENOMENA (1983)
.Lamberto Bava's DEMONS (1885)
.HUMUNOIDS from the DEEP (1980)
.RETURN of the ALIEN's DEADLY SPAWN (1983) Ultra low budget....so what? A classic!
.MANIAC (1980) If a horror movie means horrifying...then this definitly fits the bill! Joe Spinelli is terrifying and totally beliveable!
.DEAD and BURIED (1981) Am I the only person who likes this movie?
Here's the opening scence...