Considering the reason he remembers is because he saw her topless is chapter 1, I imagine more people actually remember and just pretend they don't notice. Or that explanation was a lie.
He cleared the 100, took the optional visit to 1 previous world before returning to his own, and then used his last skill to reset his whole loop. So he hasn't cleared the challenge.
@Kizuwono The FIRST chapter says he has 6 months to a year without the surgery, and with it he'll have a 30% 5 year survival chance, and no chance of an actual cure.
It's been bugging me that they keep trying to stop him from doing "dangerous" things, but can somebody with more insight just tell me if they're really just trying to keep him from bankrupting the guild again?