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