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