Incredible puzzle game! Reminds me of the Zachtronics games. There's a lot of depth to the mechanics.
Definitely challenging; it took me a good two hours to get to the end. The difficulty curve for me was very spiky: some levels took me under a minute, while I was stuck on others for 20+.
I'm glad you allowed skipping levels through the level selection, because I couldn't figure out "Shrub" or "Butterfly" for the life of me, and I encountered a bug where "Star-Crossed" wouldn't complete even though all remaining blocks were zero (I had a swap block left, though).
I found it challenging to keep track of all the operations, especially in the later levels when many things are happening on each tick. Maybe an animation for each operations would help.