Exactly.The fun of the challenge, and the way it changes the game is the whole point.So its not something to grind through to get a special item or something.At least thats all we understand it to be at the moment.There may be something...but unlikely.
It's "unlikely" there's a reward when the game states unequivocally there
is a reward before you even get out of the first room?
Nobody's asking if there is a reward, there is, they're asking what it is. It's an achievement.