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)
Unlock All Stars (Swamp)
Find All Hidden Secrets
Collect All Gun Colors
Visit the Shrine of Lovely Planet
Drink the Sake (Swamp)
Unlock All Stars (Forest)
Find the Dagger with the Pearl Inlay (Forest)
Parry Projectile at Right Angles
Find the Hungry Samurai (Village)
Find the Graves (Village)
Shoot Yourself
Unlock All Stars (Village)
Unlock All Stars (City)