Here is the full list of all 28 Demon's Crystals achievements.
You have defeated 60 spiders. Are those really supposed to be big?
You have defeated the boss Sarkon. Did those bones hurt too much?
You have played 10 matches. You are getting the hang of the game already.
You have collected 1000 crystals.
You have defeated 500 enemies.
You have defeated 80 skeletons. At least they don't leave stains on the ground.
You have defeated 30 ghosts. Only kids are afraid of them!
You have defeated 5000 enemies.
You have defeated 30000 enemies.
You have collected 10000 crystals.
You have collected 50000 crystals.
You have defeated the boss Ghoros. Dragons, meh. They don't impresss anyone with some little flames.
You have defeated the boss Ornak. Now who's the boss?
You have finished the game on normal difficulty. Congratulations on finishing the game. The Urican have saved the day!
You have finished the game on hard difficulty. Wow, not bad. However, there are more difficult challenges. Try them out!
You have finished the game on extreme difficulty. Now that's some skill!
You have finished the game on all the difficulties. You are the true master of Demon's Crystals!
You have played all the game modes. Did you miss those local multiplayer game sessions with your friends?
You have defeated 100000 enemies.
You have collected 150000 crystals.
You have played 50 matches. You are unstoppable!
You have defeated 30 armors. They are only pieces of junk.
You have defeated 70 trolls. They are as ugly as easy to defeat.
You have used all the weapons. Tons of ways of defeating your enemies.
You have revived a partner 50 times. You don't like to leave your friends behind.
You have leveled up all the characters to at least level 30.
You have leveled up all the characters to at least level 60.
You have leveled up all the characters to at least level 90.