The 3 bosses are two henchmen; One of these guys is more deadly than the other, mostly the fast moving, boomerang/knife chucking guy. He'll be your problem for the most part. Things to note when fighting these guys are:
-They bring their friends: several times the fat guy will call his friends to try to get several shots on you. Be careful!
-Some stuff to combo off of, there are paint cans and other stuff to combo more hits off these guys so if you really want that high score, this can help you.
-The boomerang/knives that the fast guy throws can be shot at. One bullet will drop 'em to the ground but I'll stress this again: don't throw away a life just to shoot a projectile. It's not worth it.
-Know when to duck: the fat henchman will try to swing a bunch of things at you. Don't be fooled, yet don't sit too long. Get a feel for when he swings and get ready to duck.

Note: The game doesn't say "DANGER!" this time.