The polish and presentation on this is top notch! The difficulty seems way too much right now. Needing all 3 hearts to complete a level feels exceedingly punishing for an already challenging game. Other than that, the controls feel solid and everything comes together really nicely!
The game's difficulty is different to everyone, and like you said it does feel punishing at times. I'll definitely add an 'easy,' and a 'hard' mode in the next update. Where in, in 'easy' mode your can have any amount of hearts, where as in hard mode you'll require full health. Thanks for the great feedback!
Edit: I've now released an updated build which includes a difficulty mini menu :)