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