Hey there I just got done playing your game and i really liked it even if i don't play that many deck building games. I Must say it was fun. Firstly I have to say the main menu is gorgeous and i really like it with the perspective, colors and everything. I like the pixel art and realistic drawn BGs it looks good together.
But i also had some issues while playing. Due to my lack in deck building I noticed it would be good to show in the start what to do and what each icon is or even a hover option over them would help a ton.
Also did I come across this:
I played till volcano area and it generally was not as hard for me. Generally rather try to make a polished shorter experience then longer one.
Regardless of all things i really had fun playing. I hope my feedback helps you and good job!!!