Heck yeah! This is great!
For some reason, it took me a while to realize I could rotate the pieces, even though I saw that you could rotate them in a screenshot you'd posted earlier XD
I loved the little "infinite loop" note :)
I liked the unlocking difficulties.
If you feel like it, I think it would be handy to have a level reset button that either resets the same level or gives you a new one. Just something to do if you know you're gonna fail other than needing to place the remaining tiles.