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
Collect All Gun Colors
Drink the Sake (Swamp)
Find the Dagger with the Pearl Inlay (Forest)
Find the Graves (Village)
Find the Hungry Samurai (Village)
Unlock All Stars (Mountains)
Shoot Yourself
Unlock All Stars (Swamp)
Unlock All Stars (Forest)
Unlock All Stars (Village)
Unlock All Stars (City)
Parry Projectile at Right Angles