How bad is it? Cheesy trash, but better than most Ulli Lommel films.
Should you see it? It's hard to find and not worth the search unless "The Apple" is a favorite.
Eventually, every Ulli Lommel film will have someone claiming it's a bad film classic. This is one of his earliest films, before horror and Nazisploitation, and he stars in it as well. A hypnotist is cryogenically frozen in Nazi Germany and then thawed in the present time by a guy who wants to convert punks, homosexuals and anyone else he doesn't like into his way of thinking. In the end, everyone is converted TO punks and homosexuality, including the lead villain. There's a ton of musical numbers, which aren't bad, but aren't quite what would fit with the film's theme, either. There's some laughs to be had in the earnestness of the kitschy characters, but it's more an oddity than a trash classic.