To run it, you'll need to have an Android device that's at least 6" or larger. Like the other platform versions, the Android edition of Hearthstone will sync up with your Battle.net account and allow you to use your existing cards (if you have any). Plans are in the works for an Android version to work on smaller-size phones.
Hearthstone recently won the award for Massively's Best Pseudo-MMO of 2014. Android players can snag it on Google Play or through Amazon.