Here is the full list of all 19 LoveKami -Useless Goddess- achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Begin the game.
View the opening movie.
View the ending movie.
Open the gallery.
Open the config screen.
Open sound screen.
The first tip displays.
Finish the common route.
Complete first playthrough.
Clear Akane's route.
Clear Inori's route.
Clear Maika's route.
Clear all routes.
View the first event scene.
View 20% of event scenes.
View 40% of event scenes.
View 60% of event scenes.
View 80% of event scenes.
View 100% of event scenes.