Here is the full list of all 42 The Last Hero achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Mute
Go Left
12 Lvl completed
End Game
Music 12
Last Step
11 Lvl completed
Music 11
10 Lvl completed
Music 10
9 Lvl completed
Music 9
8 Lvl completed
Music 8
Bandit 3 Dead
7 Lvl completed
Music 7
6 Lvl completed
Middle Game
Music 6
5 Lvl completed
Music 5
4 Lvl completed
1/3 of the game
Music 4
3 Lvl completed
Music 3
2 Lvl completed
Music 2
Game Over
First Death
Bandit 1 Dead
Bandit 2 Dead
Jump
1 Lvl completed
Go Right
First Restart
Pause
Pause 2
Music 1
Fall
Start Game