Here is the full list of all 53 Puzzle Quest 2 achievements.
Complete the "Stuff of Nightmares" quest
Defeat an opponent while on 1 Life Point during any single player game mode
Upgrade an item
Clear the town of Goblins.
Be defeated by an opponent on their first turn during single player quest mode
Defeat an opponent on your first turn during any single player game mode
Lose to an opponent who's on 1 Life Point during any single player game mode
Make a match of 8 gems in a row in any battle game mode
Learn all the bonus spells
Defeat 500 monsters
Defeat King Godd
Defeat Shadowbringer
Complete the game
Defeat the Yeti
Defeat the Green Dragon
Choose the Bash mini-game whenever possible during the single player campaign
Win 5 Tournaments
Survive the Endurance mode
Defeat 5 opponents in multiplayer
Respec your hero by visiting Jarrum Blackstone in the Chapel
Heal some trap damage by visiting Jarrum Blackstone in the Chapel
Pick your way through 5 locks
Bash your way through 5 locks
Magically force your way through 5 locks
Disarm 5 traps to avoid being wounded
Search 5 rooms for hidden treasure or danger
Defeat 1000 monsters
Defeat 2000 monsters
Finish the single player campaign with a hero from each class
Finish the single player campaign with both male and female from the one class
Watch the credits sequence to the end
Upgrade an item to Epic
Play the "Lucky Dip" side quest
Visit every room in the game
Complete the game without activating an item
Advance to the Green Dragon in Endurance mode on full health
Resist Subjugate or Crushing Kill
Win a Tournament with the first or second hero alive
Activate 5 traps during a campaign
Do more than 250 damage during your turn
Kill an undead monster, then kill it again and again after it reanimates
Lose the burning inn challenge battle
Defeat a Yeti after at least 100 turns have passed
Complete the "Able Replacement" quest
Defeat the monster known as "Teh SkullBrekker"
Complete the "Eye of the Owlbear" quest
Forge the "Hammer of Righteousness"
Defeat the Arch Lich
Complete the "Imp!" quest for Crye
Escape the Dark Dwarven Laboratory
Complete the "Insurance Fraud" quest
Gain access to Gorgons Cathedral
Complete the "Deep Delving Dwarf" quest