I don't agree on that. Of course, if someone wants to bypass a puzzle they can, but that's not the spirit in which I read the "no tutorials or hint systems" bit

I don't agree on that. Of course, if someone wants to bypass a puzzle they can, but that's not the spirit in which I read the "no tutorials or hint systems" bit. What he's really offering is the option for the player to elect to never see hints and training, and puting the constraint on himself that he has to use gameplay and good design to explain the problems and not beat you over the head with the solution. I believe his goal is not to make it more fun by making the "finished this game" more exclusive, but rather make it more fun by designing it to be intrinsically fun for the audience he's targetting.