Here is the full list of all 15 Muv-Luv achievements.
Completed the CG Gallery
Saw all possible endings of UNLIMITED
Saw all possible endings of EXTRA
Saw one possible ending of Unlimited
Unlocked Jukebox mode
Saw Chizuru ending in EXTRA
Saw Kei ending in EXTRA
Saw Miki ending in EXTRA
Started Unlimited
Saw Meiya ending in EXTRA
Took five Drill Milky Punches to the face
Saw Sumika ending in EXTRA
Saw Common End 1 ending in EXTRA
Saw Common End 2 ending in EXTRA
Started Muv-Luv!