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