Here is the full list of all 14 Clea achievements.
The base game contains 13 achievements, and there is 1 DLC pack containing 1 achievements.
Completed chapter 1 on Arcade Mode.
Reached the good (incomplete) ending.
Completed chapter 6.
Completed chapter 5.
Completed chapter 4.
Completed chapter 3.
Completed chapter 2.
Unlocked a bronze, silver or gold reward.
Completed chapter 1.
Reached the bad ending.
Reached the good (complete) ending.
Completed chapter 1 on Chaos Mode.
Completed chapter 1 in under 3 minutes.
Completed chapter 1 in War Maiden Mode.