That must be one big tavern.

Blizzard Entertainment announced today that its free-to-play digital card game Hearthstone: Heroes of Warcraft has reached 20 million players between its PC and mobile platforms.

The game launched for Windows and MacĀ in March, and it arrived on the iPad in April and Windows 8 touch platforms in August. Mobile OSX and AndroidOS versions launch later this year.

Players take on the role of heroes and assemble a group of minion and spell cards to battle others in turn-based combat. While they don’t trade cards, players can destroy cards to create new ones. Or they can buy packs or win them in the Arena mode.

The game is free to play, with in-game purchases available for card packs, Arena entries, and single-player “adventures.” The first such adventure, The Curse of Naxxramas, cost $7 or 700 in-game gold per collection/wing of bosses in the five-wing dungeon, with discounts available for multiple wings.

Finalists in the Hearthstone World Championship will compete at BlizzCon 2014 on Nov. 7 and Nov. 8 for a prize pool of $250,000.