Here is the full list of all 15 Libra of the Vampire Princess achievements.
Played game 30 hours
Cleared Lycoris route
Selected Lycoris route
Cleared Aoi route
Selected Aoi route
Selected Aoi & Lycoris route
Cleared Mari route
Played game 10 hours
Selected Mari route
Cleared Calen route
Selected Calen route
Played game 1 hour
Shut down game first time
Watched opening movie
Started game first time