I used Painwheel on the treasure node in Painwheel's daily event, there is this modifier called Biofeedback that can reflect crit damage... oh well it would be hard. My enemies were Parasoul and Cerebella, don't remember their name. I killed Parasoul without too much problem, lose about 25% HP due to Biofeedback. I had some difficult fighting Cerebella but I finally managed to beat her (she only had 1% HP left), when I hit her and thought I would win, it said I lose... because of Biofeedback that reflected my crit hit. Wait a minute, is that what it was intended to be. It is so unfair, reflecting damage should be caculated after damage is applied on opponent, players shouldn't lose if both fighters die at the same time.