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