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