Roger Corman's attempt to kick start his own comic book franchise is a quite fun cheesy bit of action - a Catwoman rip off to be sure, but who cares. Joan Severance is an attractive, viking-esque lead, looking splendid in black leather as she runs around beating people up in the name of crime.
Her day job is being a cop - which involves her going undercover as a hooker. I think that's a key flaw to the movie - her "alter ego" isn't that different from Black Scorpion... it might've been more effective if she'd been a nerd or quiet or someone very un-obviously a crime fighter.
Garrett Morris is fun as the Black Scorpion's gadget guy. I also liked Bruce Abbott as the cop who loves Scorpion - these roles can be thankless, but Abbott actually seems to have some balls and isn't emasculated by chasing after this female vigilante.
The low budget occasionally hurts - you want more spectacular stunts and fight scenes. Severance isn't the best fighter - where she karates a couple of women it looks very slow. The villain (another super hero) felt underserved.
The film is better when it focuses on being a more New World-type picture- such as Severance pashing Abbott then later straddling him and having her way with him, or the camraderie between Morris and Severance. It's one of those movies you wish were a bit trashier and sexier. But it is fun.