Cool game! This is a cool idea. And the art is great! I know you said it's still kind of a demo right now - the only thing I noticed to suggest was that the opponent is able to draw their own cards from the deck. I noticed they weren't collecting anymore to fill their hand and I could do it for them. 

I love the fusion of deck building with a simple rock paper scissor. I could have fun using my deck to super powering up one or more of the rock/paper/scissors while hoping the opponent cant counter me. Multipliers on a draw could be fun strategy as it might give you an extra advantage when you try to break the draw.

I like the ideas for the cards affecting, but not overriding, the basic triangle to Rock, Paper, Scissors. I noticed the player and the opponent are given the exact same cards in the same order and that is a pretty important thing to change to simulate card game mechanics. It would be interesting if different characters had different decks later on in development.

I'm glad the starting difficulty was low enough for me to win against the first (and currently only available) opponent on the first try as the frustration of guessing incorrectly is an inherent danger to the concept.