Here is the full list of all 29 Rune Classic achievements.
Complete the game (any difficulty).
Complete the game on Medium difficulty.
Complete the game on Hard difficulty.
Defeat Sark Conrack.
Become Sark Ragnar.
Defeat the Dark Dwarf.
Defeat the Trial Pit Beast.
Get all the weapons in the game.
Drink 25 Steins of Mead
Obtain all the Runes of Health
Behead 100 opponents in multiplayer.
Kill 100 enemies while Berzerk.
Behead 25 opponents in multiplayer
Kill 25 enemies while Berzerk.
Kill 100 opponents in multiplayer.
Make your way through Hel's Chamber
Kill 250 enemies.
Kill 100 enemies.
Avoid the Dealy Dangler Fish.
Eat 25 Lizards.
Kill 25 Enemies.
Kill 50 opponents in multiplayer.
Get "First Blood" 10 times
Get a 10 player kill spree in multiplayer.
Behead 10 opponents in multiplayer.
Defeat an enemy by setting them on fire.
Beat an opponent to death with a severed limb.
Kill 10 opponents in multiplayer.
Get beheaded in multiplayer.