Man, I really enjoyed this one. Being a huge slay the spire fan, I immediately recognized the similarities and I really liked the twist you put into the systems. Having 3 characters with each their own energy and cards was a very nice layer of strategy as well as the jewel system, the upgrade system and the hero empowerment. Really awesome all around.
Controls wise I think it handled just like slay the spire. Cards can be played in quick succession, everything felt smooth and worked as it should.
If I had to critisize anything, it would be the the audio and the UI. I found it a little annoying that the "hitbox" for the enemy tooltips to pop was so massive, that I felt I always had to put my cursor on top of the screen to actually look at the nice art you got going, which is bad, because my cards are at the bottom.
The one music track I got to listen to sounded very generic and the loop seemed very short, so it kinda got boring to listen to really quickly.
I think you got an amazing game in the works. Wishlisted immediately.