Here is the full list of all 25 Epic Quest of the 4 Crystals achievements.
Acquire the Scuba Mask.
Acquire 2000 Points.
Complete the game.
Defeat 400 enemies.
Complete the thirteenth stage with Platinum Ranking.
Complete the twelfth stage with Platinum Ranking.
Complete the quest "Moving On".
Collect all 12 Uber Rare Accessories.
Complete the eleventh stage with Platinum Ranking.
Complete the tenth stage with Platinum Ranking.
Complete the ninth stage with Platinum Ranking.
Play a New Game for 10 hours.
Complete the seventh stage with Platinum Ranking.
Complete the sixth stage with Platinum Ranking.
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".