Head On was a grand affair. Reminded me in many ways of 2, but with the speed and such of Black.
The port of Head On with the "lost Black chapters" and other bonus content was something I didn't get, though I'd been meaning to. I don't have a PSP anymore, either, so I should prolly get it someday if I ever wanna do the Head On stuff again. Also, the bonus features have cutscenes that didn't make it into the first game. They look like Troma movies.