U get the most XP by playing every level for the first time.
When you're done with the human difficulty on one a level repeating it will gain less xp.
Unless u Crank up that Difficulty.
The Higher the difficulty the more xp you get.
So more players in the team is recommended if you're going for death or insane difficulty
and do not have a high enough rank causing you to get killed by an enemy or get dropped over a letch and lose you're winnings.
Making me think?! After Happy Wars everybody fell in Happy Dungeons, but what's underneath that, when we fall from the HD-letches again, Happy....?