Meet the following conditions to unlock the following rewards.

Reward	How to unlock
Arena Mode	Unlock every Hero.
Better Daily Quests	Win 50 games against human players in Play Mode. This unlocks the ability to get daily quests with larger gold rewards
Big Winner Achievement / 300 Gold	Win 1000 games in any mode.
Captain's Parrot card (2x Golden)	Acquire a Golden version of every Pirate card in the Expert Set.
Captain's Parrot card (2x)	Acquire every Pirate card in the Expert Set.
Chicken Dinner Achievement / 300 Gold	Win 100 games in any mode.
Class-Specific Basic Cards	Level the corresponding class. Cards are unlocked at levels 2, 4, 6, 8, and 10.
Crafting Time Achievement / 95 Dust	Disenchant a card.
Crushed Them All! Achievement / 100 Gold	Defeat every AI Hero on Expert difficulty in Practice Mode.
First Blood Achievement / 1 Card Pack	Complete a game in Play mode.
Gelbin Mekkatorque card (Golden)	Purchase a pack or arena entry during the Beta perioid with money.
Golden Class-Neutral Basic Cards	Level every class to Level 60. Cards are unlocked at levels 53-60 for Mage and Warrior, and 51-60 for other classes.
Golden Class-Specific Basic Cards	Level the corresponding class. A complete set can be obtained at Level 52 for Mage and Warrior, and Level 50 for other classes.
Got the Basics! Achievement / 100 Gold	Collect every card in the Basic Set. This can be accomplished by leveling every class to level 10.
Level Up Achievement / 100 Gold	Get any class to level 10.
Mage Class	Complete the tutorial.
Old Murk-Eye card	Acquire every Murloc card in the Expert Set.
Old Murk-Eye card (Golden)	Acquire a Golden version of every Murloc card in the Basic and Expert Sets. (This requires a LV53 Warlock, LV51 Priest, LV53 Paladin, and LV53 Rogue).
One of Everything! Achievement / 100 Gold	Collect every card in the Expert Set.
Ready to Go! Achievement / 100 Gold	Unlock every Hero.
The Duelist Achievement / 100 Gold	Play 3 games in Play mode.
Unlock Additional Classes	Defeat the desired class in Practice Mode or Play Mode.