The unflinchingly grim 1986 film Combat Shock (originally titled American Nightmares) is my favorite of all the Troma releases.
Writer/director Buddy Giovinazzo's film portrays a cold, violent world in which Frankie Dunlan (played by the directors brother Rick Giovinazzo) trudges through an absolute shit sandwich of a bad day, compounded by horrific flash backs to his time fighting and then being tortured as a P.O.W. in Vietnam. Betraying the Rambo-esque one sheet art, this film occupies the same dark places as both Eraserhead and Street Trash. It would make a sick double feature with either.