Yes, there are all kinds of B movie slip-ups (like school being in session in the middle of summer, the crippled and deformed blind kid who somehow has been equipped with a sixth sense after a fireworks accident the previous July 4th, and the casket being dropped off and kept in the sister's living room as if it were a new TV set or piece of furniture) but I found myself ignoring all the flaws because the actors had so much conviction in their roles, and because Lustig's camerawork was so fluid and put me under its spell. The image of that Uncle Sam on enormous stilts first peeping into some bedroom, then hobbling away from some mysterious pursuer is one of the most effective, haunting visuals I've seen in a long while.
I was aware of his reputation for sleazy shlock but the surprise here is how much restraint and sensitivity Lustig shows in so many of the scenes (though admittedly not all). Working with a typically insightful/erratic/cliched/inspired/absorbing/impossible-to-pigeonhole script by the infamous Larry Cohen, you can tell that they really have something on their mind here other than just another slasher film ripoff. There are wonderful, quiet scenes like the one where Isaac Hayes' one-legged veteran takes the impressionable kid aside and explains that killing machines like his Uncle Sam aren't heroes at all, or the one where Timothy Bottoms' grade school teacher is forced to defend his pacifist stance during the Vietnam War to a class of skeptical students. And there are just clever, little tongue-in-cheek details throughout that clue you in (if you're paying attention) to the fact that the filmmakers put real thought and consideration into the exercise.
Whatever external flaws it may have, beneath its goofy premise there's real merit here. This is a movie that possesses something which many of its big budget counterparts wish they had: a pulse.