Here is the full list of all 25 Epic Quest of the 4 Crystals achievements.
Acquire the Scuba Mask.
Complete the game.
Acquire 2000 Points.
Collect all 12 Uber Rare Accessories.
Complete the thirteenth stage with Platinum Ranking.
Complete the twelfth stage with Platinum Ranking.
Complete the quest "Moving On".
Defeat 400 enemies.
Complete the eleventh stage with Platinum Ranking.
Complete the tenth stage with Platinum Ranking.
Complete the ninth stage with Platinum Ranking.
Complete the seventh stage with Platinum Ranking.
Complete the sixth stage with Platinum Ranking.
Play a New Game for 10 hours.
Defeat 200 enemies.
Complete the fifth stage with Platinum Ranking.
Complete the fourth stage with Platinum Ranking.
Play a New Game for 5 hours.
Complete the third stage with Platinum Ranking.
Complete the second stage with Platinum Ranking.
Complete the first stage with Platinum Ranking.
Defeat 25 enemies.
Play a New Game for 1 hour.
Finish Loras’s tasks.
Complete the quest "Rats in the Basement".