I played medium difficulty. The cards kinda just flip over randomly sometimes, I think this is the magic effect mentioned, but it was hard to tell exactly what happened. Also at one point there were only 3 cards face down and I wasn't able to flip anymore over. I like the game concept as a whole though! Also side note, the viewport size for the browser is far larger than the unity window size. I had to zoom out a lot to play. Fun game!