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