Here is the full list of all 14 Lovely Planet achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Unlock All Stars (Mountains)
Find All Hidden Secrets
Visit the Shrine of Lovely Planet
Collect All Gun Colors
Unlock All Stars (Swamp)
Drink the Sake (Swamp)
Parry Projectile at Right Angles
Find the Dagger with the Pearl Inlay (Forest)
Find the Hungry Samurai (Village)
Find the Graves (Village)
Unlock All Stars (Forest)
Unlock All Stars (Village)
Unlock All Stars (City)
Shoot Yourself