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