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.
Buy the highest armor upgrade available.
Reach Level 30 in any character.
Reach Level 30 in every character of your group.
Visit every single place in game.
Kill a dragon.
Reach Level 30 in a trio.
Play with all characters in game.
Reach Level 15 in a specific Spell.
Spend 9.001 golds.
Earn 9.001 golds.
Clear 10 dungeons.
Unlock the Shaman class.
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!
Play with all classes in game.
Unlock the Necromancer class.
Unlock the Knight class.
Unlock all masters.
Clear a dungeon.
Unlock a new master.
Unlock the Hunter class.
Choose a weird combination of character and class.
Reach Level 15 in any character.
Unlock the Bard class.
Gather 10 grindstones from veins.
Unlock the Barbarian class.
Use a potion while full health.
Unlock the Game Developers that made the game.
Make the blacksmith dance.
Roll 1 in any random roll.
Roll 20 in any random roll.
Gather a grindstone by mining veins.
Win a battle with 7 monsters.
Reach Level 5 in any character.
Kill an elite minion.
Continue the game after a game over.
Complete a campaign using all 5 Game Developers as characters.
Visit your Kitchen inside the game.
Buy the highest weapon upgrade available.
Finished the campaign.
Finish the storyline as fast as you can (less than 365 days but you may extend that to 465).
Buy all goodies in game.
Clear 50 dungeons.