I was reading a few of the games that are being played and I had some issues using my iphone.

I had a little trouble with viewing any of the cards in a particular scene. The first issue I had was figuring out how to close the overlay. I kept trying to tap outside the overlay to close it - it took me a bit to realize the link to open the card would also close it. Perhaps a standard 'X' in the overlay to close it would be beneficial to users?

Additionally, I noticed that when turning a card over, the browser would jump to the top of the page which I then had to scroll back down to read the back of the card.

This probably isn't an issue with larger screens but it got annoying on my iphone.