Hey! Really well executed game. The gameplay feels really solid and the sound and music are great!
At times I was tempted to brute force my way through some puzzles. Could be that I just wasn't prepared for a challenge right now (or in life in general :D), but could also be that some puzzles are a bit too hard to grasp. E.g. C05 was really difficult for me. I tend to first just try something pretty randomly and when it fails, I try to change something in my approach. But the problem in that level was that I quickly forgot what I had already tried, so it made it difficult for me to adjust my approach. The undo function might help with that, but I only discovered that pretty late in my game session. So maybe undo is a bit too hidden.
Also, even though the graphics are very clear and well crafted, the game doesn't look particularly appealing to me. Even though the meat of the game is in the puzzles, having a bit more atmosphere in the graphics and maybe some little satisfying graphical details might help me get emotionally invested in the game.
Keep at it! It's a really unique and surprisingly deep puzzle concept!