The main problem was that the game was limited to certain countries as part of a soft launch that began last year.
Well, starting today you can finally get it worldwide now on iOS and Android.
If you've not been following, Clash Royale is a sort of mix between a DOTA lane based strategy game and a TCG.
It's effective at being quite addictive and its free to play system is mostly harmless with no energy meter in place.
I'd really encourage you to try it, you might be surprised: