The artwork here is very impressive. The color palettes on the carnival and ethereal designs on some of the enemies are very striking and memorable.
I like the core concept of drawing cards during combat to enhance the outcome. Slow-mo while selecting the card to play could help since it is likely a tool-tip or legend for what cards do what would be needed.
The final (I think) boss had a nice visual payoff, but the difficulty didn't require using any cards since he can be stun locked against the wall.
The opening to the music had me thinking we were about to hear "My Heart Will Go On", sets a good mood though.
Definitely a promising direction and prototype of the concept.
Oh, and what was the process for the incredibly detailed pixel art on the cards?