Incredible game! I've never played a metroidvania where you can entirely figure out what upgrades you need and how to get them just by looking at the map screen, until now. It's so elegant.
Spoilers:
I accidentally read the rule of how the transformations are allowed before playing, and imo it made the experience much better for me that i knew the 2-overlap rule outright. There were enough other things to figure out in the game already that were fun when knowing that rule.