The last movie in the Bloodsport series is also (and predictably) the weakest. Daniel Bernhardt returns once again as Alex Car..oops, sorry as John Keller (!?). Yes, the name of his character changes, for no apparent reason (This also happens in the American Ninja series. My theory is that this IS Alex Cardo, but something happened between 3 & 4 and he had to change his name).
This fact aside, Bloodsport 4 : The Dark Kumite, goes the route of the "cop undercover in prison" and handles it pretty well. What's wrong then? Well, the "dark kumite" the title promises is really quite bad: very few fighters, even fewer good fighters, and fights so short you'll miss them if you blink.
However, outside of this failed kumite, the movie's alright, and if you've enjoyed Bloodsport 1, 2 & 3, and don't expect too much out of 4, you should check it out.