Originally Posted by
vash
Removing kills is being part of one good method to prevent cheaters to have any kind of advantage, this method is mostly useful on top kills when many players could have big amounts of donations (kills) even if they don't know the some of those players, this means you can play for top kills without being preoccupied who you kill and if those guys are playing clean.
Once you have completed a level, for now, there isn't any other way to go back if you don't want, resetting levels are done ONLY when you change the profession.
I hope you will understand that this is not a "new design" but a way to avoid advantages from cheaters or who want to help them with more kills.