How bad is it? It has some of the worst dialogue ever (written by Wayne Rogers of "M*A*S*H" fame).
Should you see it? Yes.
Carradine's assistant is not a hunchback, but stoops anyway and he squints one eye and goggles the other, he's mute and he's doing his own experiments, which consist of tying a girl in a bikini to a table. Tura Satana changes from one ridiculous outfit to another and tries to act tough; one sees the talent of Russ Meyers in getting such a great performance from her in "Faster Pussycat, Kill! Kill!" by comparison. The zombie has a battery that is solar powered; in the climactic scene, it has to hold a flashlight to its head to keep going and it's impossible to see it as threatening at that point!
The movie spawned three sequels decades later, which I haven't seen.
Mikels directed several films at the start of the alphabet:
Aftermath (1982): post-nuke biker film. Not bad.
Angel of Vengeance (aka WarCat) (1987?): Survivalists vs. bikers. Dull.
The Black Klansman (1966): a light-colored black man infiltrates the Klan. Fair.
Blood Orgy of the She-Devils (1973): good title, poor film about a witches coven.