I had already found all six endings before the badge. If you are having trouble with the badge awarding: try reloading the game a second time...it worked for me...
@jaggalier: Thanks for your suggestion. Needed that one to get the badge. For level 22 you just have to use each weapon to kill at least two enemies. ie: start with chainsaw and kill 2 guys, switch to pistol and kill two guys, etc....it helps if your weapons are all maxed.
 "Far Orion"){kind=icon}
 "Crush Crush"){kind=icon}
 "Revenge of Dog"){kind=icon}
 "The Final Death Wish"){kind=icon}