Coming with the Madness at Darkmoone Faire is Hearthstone's new Achievement system! Here is a quick run through of how the whole system works.
So far, there are 5 main different types of achievements, these being Progression, Gameplay, Collection, Adventures, and Game modes. Each time there is a new expansion, including the mini expansions that are new to Madness at Darkmoone Faire, a new batch of achievements will also become available. Completing each achievement will also reward you with a certain amount of achievement points, which are either cosmetic and are essentially bragging points, or can be used to unlock things, we are not sure yet.
Currently, we do not know anything about what the progression achievements are about. This guide will be updated with information about them as soon as it is available.
These achievements are based around doing specific things in a match, such as killing the opponent with C'Thun, the Shattered or resurrecting 6 minions with N'Zoth, God of the Deep. There are also gameplay achievements for each specific class, requiring you to once again do specific things with the class cards.
The collection achievements are milestones for collecting certain cards and for expanding your collection. An example of one of these types of Achievements is with the new collectible coins, which you can get for collecting 135 cards from a set. As for these collectible coins, they work in a similar manner as card backs, being able to chose to use certain coin skins for your decks.
The gamemode achievements are based around certain accomplishments within any of Hearthstone's game modes. It covers all of Hearthstone's modes, even including Tavern Brawl and Arena. An example of some Battleground achievements are getting a copy of Curator's Amalgam or placing 30 hats on a minion Dancin' Deryl.
Last but not least, we have the achievements for the solo adventures. We currently do not know of any of these achievements, but will update as soon as possible.
For more information about the new progression system, here is a link to our guide on it!