Here is the full list of all 31 Magicka: Wizards of the Square Tablet achievements.
Multiplayer: Have the green wizard never die or cast a single spell and still win the stage.
Multiplayer: Telefrag a fellow wizard.
Multiplayer: Kill a fellow wizard.
Multiplayer: Die at least twice as often as all your teammates combined.
Multiplayer: Have a team of four wizards all die.
Multiplayer: Deal at least 800 damage to a fellow wizard in one attack.
Multiplayer: Have the yellow wizard die first in a stage's very first encounter.