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