Very nice game, it kept me entrateined for a couple of hours, that for a demo is an amazing time.
About the game, balance could be better (on both your card and enemy) but is already in a good spot.
Most of my suggestions would be about quality of life details, like giving more info about keywords (like the explosion ability), and maybe the possibility to see how card can be improved at the camp fire (more then once i didn't risk a card becouse i feared that the power up was actually a downgrade for my deck: i.e. wand into dagger wand).
I like the idea that everything can be moved on the field, but sometimes it can get a little bit chaotic, especially with summon builds, very strong, but when you have 5 or 6 down they start to overlap eachother and it's hard to see what is going on or to target one specific summon (with clay for exemple)
Very good game tho, keep up the good work