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.
Reach level 100
Get 10000 gold coins
Reach 500 followers
Get 5000 gold coins
Reach 10 followers
Get 1000 gold coins
Defeat the final boss
Kill the Giant
Eat a blue mushroom
Buy a treasure map!
Reach level 50
Forge a legendary sword!
Become a Lord Knight
Drink a beer
Forge a great sword!
Defeat 15 monsters
Become a Knight
Reach level 20
Defeat 5 monsters
Forge your first sword!
Become a Swordsman
Reach level 10
Reach 100 followers
Save a girl in danger