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