Hearthstone has reached over 20 million active players

Blizzard’s free-to-play card-combat game managed to reach 20 million active players so far, according to the developer. The company made the announcement on Twitter, marking the milestone with a special card.

Thank you all for joining us in #Hearthstone! We’re going to need a bigger tavern! pic.twitter.com/7OUMMIM5ww

— Hearthstone (@PlayHearthstone) September 15, 2014

Hearthstone: Heroes of Warcraft was released on March 11, 2014, for Windows and Mac OS, on April 16, 2014 for the iPad and for the Windows 8 Touch interface on August 6, 2014. The game is slated for release on iPhone and Android later this year. Blizzard has not disclosed the exact release date yet. It is notable that, only in March, the game had over 10 million accounts registered worldwide, and, by September, the number has doubled.

In July 22, 2014, Blizzard released Hearthstone’s first single player adventure, The Curse of Naxxramas. The expansion is a five-wing adventure, each one being a wing of the World of Warcraft Naxxramas mission. During the adventure, players are able to collect a total of 30 new cards. The chapters, or wings of the adventure, can be acquired using either in-game currency (gold) or real money. The first wing is free to access until September 30th. The Curse of Naxxramas expansion pack can only be accessed by players who have already unlocked all the nine classes.

Purchasing a wing unlocks it and makes it playable at any time. Completing a wing unlocks a new legendary card for the player. The chapters can be bought either individually for $6.99/chapter or 700 Gold or in packs of two, three or four. If you buy two episodes, you will have to pay $9.99, for three episodes $14.99 and for four episodes $19.99. If you choose to buy the whole bundle, you will be able to get for $24.99, but the fifth wing will not be unlocked until after you pass the first four.