Simple but fun, it's always satisfying to solve some puzzle ! Great job !
However I don't think that the HP system is relevant on a puzzle game, because I don't think it requieres a game over, the real game over is when the player give up
Well if you lose all your hearts it basically means you've lost 5 points but you can still continue.
Also it shouldn't be too hard to make 4 or less mistakes in the game and since the game was a bit easy and you could just choose both doors in the first levels I did want to make something to make the player think more. But thanks for your comment