Here is the full list of all 25 Epic Quest of the 4 Crystals achievements.
Acquire 2000 Points.
Complete the game.
Play a New Game for 10 hours.
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.
Defeat 400 enemies.
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 5 hours.
Complete the fifth stage with Platinum Ranking.
Defeat 200 enemies.
Complete the fourth stage with Platinum Ranking.
Complete the third stage with Platinum Ranking.
Complete the second stage with Platinum Ranking.
Play a New Game for 1 hour.
Complete the first stage with Platinum Ranking.
Defeat 25 enemies.
Finish Loras’s tasks.
Acquire the Scuba Mask.
Complete the quest "Rats in the Basement".