Here is the full list of all 24 Who Needs a Hero? achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Become a Lord Knight
Defeat 15 monsters
Forge a great sword!
Become a Knight
Reach level 20
Drink a beer
Reach 100 followers
Forge your first sword!
Defeat 5 monsters
Become a Swordsman
Reach level 10
Eat a blue mushroom
Reach 10 followers
Save a girl in danger
Reach level 50
Reach level 100
Buy a treasure map!
Forge a legendary sword!
Get 1000 gold coins
Get 5000 gold coins
Get 10000 gold coins
Reach 500 followers
Defeat the final boss
Kill the Giant