I’ve often read the concept of “challenging the player; not the character” in some OSR blogs. Makes total sense, and I think it’s usually an aspect of RPGs that I enjoyed in the past. So, stupid question, outside of adventures crafted for solo play, like the Tunnels & Trolls or Fighting Fantasy kind, can one truly “challenge the player” when you’re playing solo? The answer would seem to be ‘NO’ in most cases as you would run into the so-called Czege Principle (http://random-average.com/TheoryTopics/CzegePrinciple). This being the case, it’s probably safe to say that during solo sessions most of the challenges will be of the “challenge your character” type, which would mean most of your enjoyment would probably come from watching the outcome of putting your character through such challenges; a little bit like playing God with your character perhaps.
However, there is a little solo game called Beloved, which shows that it is indeed possible to challenge yourself as a player: https://docs.google.com/document/d/1gnPx8AlhF1TMarQ165Y1vGM382c6epUvCu1-HkXvICI/edit?hl=en&authkey=CJDYi58F&pli=1# The trick here seems to be in coming up with seemingly impossible to solve challenges (in the case of that game, an invincible monster), and then as a player, trying to figure out how the challenge is not actually impossible after all by looking for holes that you may not have been aware of before setting up the challenge.