First off, loved it. It showed all of the knowledge of a proper Metroidvania.
Started on a controller. Once I reached the first pot and brewed the first potion, I was no longer able to play on controller. Beyond that, selecting option on the menu screen with a controller was far too unweildy.
I loved the character animations for the main character and the monsters.
Some of the mechanics, like blowing yourself up for a boost, felt a bit fickle, but there didn't feel any true risk in experimenting. Overall a great game!