Michael Kallio gives a strong and convincing performance as Eric Seaver, a troubled young man who was horribly mistreated as a little boy by his monstrous, abusive, alcoholic stepfather Barry (a genuinely frightening portrayal by Gunnar Hansen). Eric has a compassionate fiancé (sweetly played by the lovely Tracee Newberry) and a job transcribing autopsy reports at a local morgue. Haunted by his bleak past, egged on by the bald, beaming Jack the demon (a truly creepy Michael Robert Brandon), and sent over the edge by the recent death of his mother, Eric goes off the deep end and embarks on a brutal killing spree. Capably directed by Kallio (who also wrote the tight, astute script), with uniformly fine acting by a sound no-name cast (Jeff Steiger is especially good as Eric's wannabe helpful guardian angel Michael), rather rough, but overall polished cinematography by George Lieber, believable true-to-life characters, jolting outbursts of raw, shocking and unflinchingly ferocious violence, a moody, spooky score by Dan Kolton, an uncompromisingly downbeat ending, grungy Detroit, Michigan locations, a grimly serious tone, and a taut, gripping narrative that stays on a steady track throughout, this extremely potent and gritty psychological horror thriller makes for often absorbing and disturbing viewing. A real sleeper.