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