This is technically a "zombie" movie, but it's one that leans more on allegory than most I can think of. It's about a young soldier, played by Richard Backus, who at the very beginning gets shot and killed in Vietnam. And, appropriately, his family gets notice from the army that he died in combat. The father (John Marley) and his daughter (Anya Ormsby) give their response of immediate grief, but the mother, played by Lynn Carlin, is refusing it, it can't be so, no way no how, they're *lying*, in fact. That very same night, the son, Andy, returns home... but as WHAT, you may ask?
How did Andy come back to life? No answer, and there's no effort on the part of Bob Clark, the director (one of his very few entries in this genre), and Alan Ormsby the writer (I assume related to the actress playing the daughter by the way), to explain this even in the brief 'radioactivity/satellites/voodoo' or so on. It's meant, I think, to be a pure metaphor for the time: this was Vietnam, of course, when Americans, as well as many more Vietnamese, were being killed by the thousands, and if people did come back they often were never the same again. Andy coming back to the family as a symbolic zombie first - he talks to his 'so happy to see you!' parents and sister in a plain monotone, with Backus looking like you sucked any of the life out of a Montgomery Clift type of actor - and then as a 'real' one, as the horror comes from Andy having to kill people and take their blood (this latter part reminded me of Martin, the Romero film, but that's another story altogether so let's not go there).
I think that there's a good amount of, frankly, cheese to this picture. There's a scene where, to show that Andy is fully disconnected from humanity when some local boys come around and the dog is bothering him and them, he picks up the dog (this is after badly testing his 'strength' against one of the boys) and strangles it to death. And while the intention is for it to be a serious moment, it's purely laughable. What does work is that Marley and Carlin - of all things re-teamed as a married couple following the John Cassavetes masterpiece FACES - play it straight and play it all sincerely, and bring real drama out of it (up to a point, to varying degrees for both of them), and that Backus also fully commits and is genuinely creepy and terrifying when he has to be.
In the last stretch, especially the last like 20 minutes, it gets progressively sillier, or just more demented or WTF or whatever, as Andy is literally melting away with maggots taking up his innards. It gets to the point where his character is set up on a double date with his sister and he has to put on sunglasses just so everyone else doesn't see how he's melting away, like a literal *walking dead* figure. The message is not exactly subtle, but aside from the grief of a parent over a child, which is made especially clear with Carlin's mother and she is delivering the real goods, yes, even when it goes more bats*** in the final stretch, it's also kind of, well, misogynistic (Marley, the dad, sort of just pushes aside his wife and daughter whenever he feels like it as an excuse of being angry about his son, to the point where he pushes one character off the screen!)
Clark and the writer have something noble to say about how families dealing (or decidedly *not* dealing) with grief over their fallen family members, especially with a war as tumultuous and wrong as Vietnam was, and some of it shows. At the same time it's also an excuse to see Richard Backus act extremely creepy and detached for 90 minutes, and while he's certainly not bad at it, he makes it today seem mostly kind of silly. I'm not sure if the filmmakers intended that, but it does make for a highly entertaining sit, especially with a packed audience.