Ranged weapons are your best friend for this trophy, even though you can go with any weapon you feel confident with. I also advice you to first level up the Pierced Butterfly to level 3 in order to obtain maximum bonus (%2) for each room.
If you are struggling with this, just turn off the auto-sync option for the game and manually upload your save file after every successful room. That way you can download and replay the last room whenever you screw things up.