Well, fuck. Hearthstone is out on smartphones and although I have played more games on my Macs than on my iPhone, but it's nice. Plus, a free pack!
The one thing I didn't quite grasp at first is that you must tap on the cards in hand in order to get access to casting them. The cards are then displayed on the bottom of the screen with available mana on the right of the screen. This covers up some information, but a tap on any non-card point scoots them back to the corner.
But that's about it. Things have been moved for the sake of user experience and fitting the interface on the screen, but it plays fine on my iPhone 6. I've played Hearthstone tethered before so I know it doesn't take much bandwidth to play a few games.
The only issue is being disconnected if you leave the game at all. Which I have done by absent-mindedly tapping the power button while playing. This has only happened once and I was able to reconnect without issue.
It's nice to be back.