JSilvis: If the bosses takes 5+ minutes, you are doing it quite ineffective. I just tried them all again with everything maxed and no one takes more then 30 seconds when optimizing it. Use the laser on cooldown, pop the shield and move into the boss and do a dubbleclick. They will die very fast.
 "The Peacekeeper"){kind=icon}
 "Death vs Monstars 2"){kind=icon}