Here is the full list of all 14 Spirits achievements.
Complete level 1 to 5 with perfect score
Collect 30 plants in any completed level
Save the middle-left spirit in the "All for one" level
Complete the "Two sides" level without using the grow action
Complete the "Three Paths" level by only using the blow action
Collect a plant in any level
Collect 60 plants in any completed level
Collect 100 plants in any completed level
Complete "Cave Story" without using the 3 top-left spirits
Complete "A Tree" level without any spirits dying against the spikes
Complete the "Downwards" level by only using the dig action
Complete level 6 to 20 with perfect score
Complete level 21 to 35 with perfect score
Complete level 36 to 43 with perfect score