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