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.
Clear 10 dungeons.
Visit every single place in game.
Reach Level 30 in any character.
Play with all classes in game.
Buy all goodies in game.
Reach Level 30 in every character of your group.
Reach Level 30 in a trio.
Spend 9.001 golds.
Unlock the Knight class.
Earn 9.001 golds.
Unlock the Shaman class.
Choose a weird combination of character and class.
Unlock all masters.
Unlock a new master.
Unlock the Necromancer class.
Clear a dungeon.
Reach Level 15 in a specific Spell.
Unlock the Barbarian class.
Reach Level 15 in any character.
Unlock the Bard class.
Use a potion while full health.
Gather 10 grindstones from veins.
Unlock the Hunter class.
Make the blacksmith dance.
Unlock the Game Developers that made the game.
Win a battle with 7 monsters.
Gather a grindstone by mining veins.
Roll 20 in any random roll.
Reach Level 5 in any character.
Kill an elite minion.
Roll 1 in any random roll.
Kill a dragon.
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 characters in game.
Visit your Kitchen inside the game.
Buy the highest weapon upgrade available.
Buy the highest armor upgrade available.
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.