I have seen Force Four (aka Black Force) about 15 times. Admittedly it has been a couple of years since I last watched it, but I still love it to bits. It's not the type of movie you would watch for realistic, or even entertaining martial arts - it's more of an example of how funny a C -grade movie can be!
I honestly find Force Four's main entertainment value to be it's complete lack of professionalism. It looks like it was filmed in one take and the cinematography is down right ugly, but that's what makes it so much fun to watch! The story line is terrible but that's not important when you have so many other things to keep an eye out for. Scenes like Billy (the girl) fighting about 12 bad guys - one minute she is wearing her orange hat, but the very next camera angle shows her without a hat at all! Pretty damn funny because it's pretty damn obvious. Basically, the film is riddled with errors and dodgy camera work. In my opinion, it has the perfect recipe for a great movie.
So if you're looking for a good laugh, give Force Four a go. I'm sure Warhawk Tanzenia wouldn't agree, but it has some of the lamest acting and fighting you'll ever see! Keep an eye out for it - it's the video (I REALLY doubt it's on DVD) with three guys on the cover (Billy is on the back).
Enjoy!