The entire series is pretty terrible gameplay wise. They're fun enough to credit feed through a couple times just to see all the goofy shit and hear the soundtracks but that's about it.
The semen cannon in the PS2 version is quite a sight.
Edit:
I wish I could find footage of it.
You wiggle the analog stick up and down rapidly to fill a meter in the corner that becomes more erect the faster you do it and when it's full your characters shoot a stream of jazz equivalent to the the zombie puking in Metal Slug 3. You basically jerk off your controller.