Good read :)

For me, I think hitting "the wall" is very demotivating. Having to look up for solutions online break the immersion and feel like cheating. It is like the reward is not yours anymore.

For me, the puzzle games that work the best were the ones with smaller puzzles, that led me to continue forcing on without feeling overwhelming.

This text also reminded me of a really good Game Maker's Toolkit video on the same theme.