In a new interview with GameSpot today at PAX East, Hearthstone: Heroes of Warcraft production director Jason Chayes opened up on the challenges of bringing the free-to-play collectible card game to Android. Ensuring that the game's interface translates to the many variations of Android devices is one of the toughest tasks, he said.

"Just the breadth of different screen resolutions, different device capabilities--all of that is stuff we have to factor in to make sure the interface still feels good," Chayes said.

"The conventions we've established between the PC and iPad versions should carry over into this new platform," he added. Maintaining a smooth Hearthstone experience, whether it's on an Android smartphone or tablet, is key, Chayes explained.

We also spoke with Hearthstone lead designer Eric Dodds, who stressed that the Android version of Hearthstone remains on schedule for a release during the second half of 2014. "That is something that we are still on track for," he said.

Hearthstone soft-launched last week for iOS. Just today, Blizzard announced a new single-player adventure called Curse of Naxxramas, and you can play without spending a penny.

Parent publisher Activision Blizzard has major ambitions for Hearthstone. CEO Robert Kotick said earlier this year that the game has the potential to become Blizzard's next "mega franchise," joining World of Warcraft, Diablo, and Starcraft.