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