What an amazing puzzle game!
I did all the levels about 2 months ago and recommended it to a friend, who then said he couldn't do #25. So I go back to see, and I don't recognise half of the levels.... Some of them were much harder... what's going on, am I going insane?!? Have I really forgotten such difficult levels in only 2 months? Then I read the new comment, hehe. Took me ages to do the new #22, now focussing on the last two: #23 and #25.
Congratulations to the author, excellent level design and playability.