Nice simple game, good as you are learning new things.
In addition to what the other have already said, I would avoid to leave so many hearths around. The game is already very easy, so I would leave maximum 2 of them.
In addition I wouldn't destroy the heart when touching it if the princess is in full heart, this because a player might leave it for later.
Good as starting point of game, you can definitely build up more from here :)