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