Very cool! Matching the same sides to unlock additional card effects is a smart idea that allows for quite interesting play, especially when you also have negative sides. I think it would be a little bit more engaging if there were more matches, as right now they are rare and I could always avoid them.
The overall theme choice and music are top tier!
One more thing: asking to press any button to continue breaks the flow a bit because you can play only with your mouse otherwise.