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