Here is the full list of all 12 Café Stella and the Reaper's Butterflies achievements.
Start a New Game
Start Kanna's Route
Finish Kanna's Route
Start Natsume's Route
Finish Natsume's Route
Start Nozomi's Route
Finish Nozomi's Route
Start Mei's Route
Finish Mei's Route
Start Suzune's Route
Finish Suzune's Route
Finish all the different Routes!