Here is the full list of all 42 Knights of Pen and Paper +1 achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Kill a dragon.
Finished the campaign.
Visit every single place in game.
Clear a dungeon.
Unlock the Shaman class.
Unlock the Necromancer class.
Reach Level 30 in any character.
Buy all goodies in game.
Unlock the Knight class.
Earn 9.001 golds.
Reach Level 30 in every character of your group.
Reach Level 30 in a trio.
Unlock the Bard class.
Buy the highest weapon upgrade available.
Unlock the Barbarian class.
Unlock the Hunter class.
Spend 9.001 golds.
Buy the highest armor upgrade available.
Reach Level 15 in a specific Spell.
Unlock a new master.
Unlock all masters.
Reach Level 15 in any character.
Gather 10 grindstones from veins.
Use a potion while full health.
Make the blacksmith dance.
Unlock the Game Developers that made the game.
Roll 20 in any random roll.
Choose a weird combination of character and class.
Reach Level 5 in any character.
Kill an elite minion.
Win a battle with 7 monsters.
Roll 1 in any random roll.
Gather a grindstone by mining veins.
We know it may be frustrating to die so we've just rewarded you with this achievement. Do not give up, the game is about to begin!
Continue the game after a game over.
Complete a campaign using all 5 Game Developers as characters.
Play with all classes in game.
Play with all characters in game.
Visit your Kitchen inside the game.
Finish the storyline as fast as you can (less than 365 days but you may extend that to 465).
Clear 10 dungeons.
Clear 50 dungeons.