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