Just finished the game. It was beautiful and quite challenging. The hard mode was almost impossible but it feels good to beat a hard game. I only have 2 "complaints".
First is that I hit those pink spikes A LOT of times cuz I coudn't see them, they are quite small and blend in with the enviroment, but that was not big of an issue, just frustrating.
My main issue was that there was no checkpoint save after I exit the game. It was a big bummer when I was at the half of the game and retuned another day to finish it, only to find out I have to play the whole game from the beggining.
Overall, a great game, great atmosphere and art, nice challenges. Nice job man, keep it up.