Here is the full list of all 24 Skull Rush achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Turn an enemy.
Own more than 3 skeletons when you win.
Now I've got 2 axes!
You need a sword and a shield.
Now I've got 2 spears!
Now I've got 2 hammers!
Now I've got 2 sowrds!
The castle fell but...
Kill an enemy with a throwing weapon.
Armed with a hammer.
Armed with a spear.
Armed with a shield.
Break a leg while landing.
A skull didn't hit anyone.
Armed with a sword.
Lose an arm.
Armed with an axe.
Win with your last skeleton.
Lose legs.
Lose both arms.
Defeated by enemy's castle.
Kill an enemy with a skull..
Kick a skull.
Lose a head.