Wow, that's really cool to read! I feel like I should have more to add, but it's quite cool hearing your experience at any rate. The scarcity of citrine in your world, and how that affected your play, is one of those emergent things that I didn't precisely plan, and that's particularly interesting to me.
As you gain in skill, you'll likely play more and more levels up, as you've been doing so far. Then again, as the game evolves and more speedbumps like the fairies are added, I think you'll find yourself dropping back down to more like-level regions for a while, adjusting your strategies, and then creeping up in what relative levels you try to take on, etc.
Anyway, great brain dump.