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