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