Thank you for playing and liking this game, and for the in-depth comment as well! This is a lot to take in but really gets into a lot of things that I didn't think about during development. Something like trying to get the balancing right, and it's actually surprising that trying to match the number is actually much feasible. I though it may be too difficult so that I leave it to the healing node only. The system do allows me do other stuff like "Smaller or equal to" but it feels difficult to balance with. And speaking of balancing, I should definite fine tune how energy is given, having too much is just making the game too easy. (Limited board is intended though. Training mode is also a good idea, should be fairly simple to do too.
Anyway, thanks a lot for the wonderful comments!