No clue what this is but seeing i have a Note 4 myself i might give it a try.
Don't know what Hearthstone is? I guess I was assuming everyone did. FYI you need to do something a little different to get it to work... but it is very simple.
Hearthstone (in my own words) is a online CCG (collectible card game) that involves strategy and deckbuilding to win. Content-wise, it is based upon WoW... but, having never played WoW, it doesn't really matter to me and has no affect on gameplay. If you've played Magic, you'll see the many similiarities. It is a fun, quick and a bit simpler version of Magic, I'd say (And I only barely know how to play Magic, never really played it).
Players face off by choosing characters that have unique deck-types with the ultimate goal to kill your opponent's character. It is deceptively simple... very quick to learn and very tough to master. Earn new cards by leveling up from playing other people, buying, earning decks, and doing adventures (the player vs ai version). You can earn gold from daily tasks, wins, the arena, or buying gold with actual currency.
Hope that helps.