I'm impressed at how in-depth the game seems to be! I struggled a bit to get a good grasp of the rules and mechanics, but with some more explanations and perhaps some clearer feedback on where each card can be placed, I think it could make a solid base for a standalone game, great work! (and the art and sound is pretty sweet as well!)
And a small note which might be useful: the game does not display too well on high-resolution screens (mine is 1440p). I think you can set the window stretch mode to "viewport" or "canvas_item" in your project settings to help with that!