Watch for Tom Hanks in a his first film role as a psychology student in this low-budgeter that tries so hard to imitate "Halloween," it even has a score that sounds the same.
A maniac who was left at the altar a while back now murders brides-to-be. Like most slashers of the era, this one tries to revolve the killings around a significant day, and in this case it's weddings. But some of the most memorable moments in the film have nothing to do with weddings. In fact, the opening of the film, set in a movie theater, likely inspired the makers of another slasher movie, "Scream 2." In fact, it clearly did influence them.
After the movie theater opening, the film switches its attention to a bride-to-be (O'Heaney) who is now the target of the maniac. She naturally has two friends who are also targeted (just like in "Halloween"). Like "Eyes of a Stranger," the film features a head in a fish tank, but isn't as much sleazy fun as that movie, which came out around the same.
"He Knows You're Alone" wasn't outrageous enough to have as much of an impact as more politically incorrect slashers like "The Toolbox Murders" or "Eyes of a Stranger." The film is for the most part devoid of gore and sleaze. Mastroianni does his darndest to make the film feel like "Halloween," striving for atmosphere over guts and blood, but doesn't have the talent of Carpenter to pull it off. Out of print on video, it's mostly remembered as an oddity and for featuring Tom Hanks in his feature film debut.
Worth catching if you're an early 1980s slasher completist, but go in with the lowest of expectations.