Here is the full list of all 22 Muv-Luv photonflowers achievements.
Completed Before the Cherry Blossoms Bloom
Completed Best Friends Forever!
Completed Never Judge a Book
Completed The Case of the Missing Tail
Completed The Yakisoba Festival
Completed Learning to Love
Completed Learning to Lead
Completed Atonement
Completed Rain Dancers
Completed Confessions
Completed Inheritance
Completed Chicken Divers
Completed all sidestories!
Viewed Schwarzesmarken PV
Checked out Gallery mode
Watched all Theater movies
Checked out an Extra sidestory
Checked out an Alternative sidestory
Opened the Save Menu
Opened the Load Menu
Opened the Options Menu
Scrolled through the Alternative Timeline