Last year I deliberately set out to make a Sokoban-derived game where the interest came from a different place than being incredibly hard. Whenever I play one of those puzzle games, I'm like *this was fun for like ten levels, why can't the rest of the game be as easy and fun as the first ten levels?"
This year, I happened on the Snakebird similarity accidentally. I would look to Snakebird for puzzle design inspiration, but I can't because it was too hard for me.