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