How bad is it? It's so bizarre that it's a matter of taste. I say it's bad.
Should you see it? If you're a fan of anyone involved, maybe.
Directed by William Lustig, who's done a lot of trash, and written by Larry Cohen, who's created some of the strangest horror films, this movie has small roles by Isaac Hayes, Timothy Bottoms, P.J. Soles and Bo Hopkins. With that combination anything could happen; what did happen was: a soldier killed in combat rises from the dead on July 4th and kills the unpatriotic after kids burned a flag at his gravesite. Why he's dressed as Uncle Sam, often on stilts, is not well-addressed. The humor and the horror are a mixed bag; for every moment when you think "oh, that was clever," there's another two that make you groan. There's a lot of logic and continuity flaws - school is apparently in session in July, for example - but not enough to make it funny.