I completely agree with you that I love that it feels like a puzzle game and the planning that goes into choosing pieces. That being said, many of the levels do feel a bit static. Maybe instead of an AI, some pieces could just have set movement paths, even if it was just in a circle or back and forth. One of my favorite levels was the giga bishop precisely because I could just maneuver around it. It was COMING FOR ME.
I really hope you do take this game farther. I enjoyed it so much!