Here is the full list of all 14 Flowa achievements.
Complete your first level
Complete fifty levels
Complete all 100 levels
Have 100 total flowers collected across all levels
Have 777 total flowers collected across all levels
Achieve the bonus goal on ten levels
Achieve the bonus goal on fifty levels
Achieve the bonus goal on 99 levels
Finish the "final" level
Blow the car up by launching it into something
Scare off a baker's dozen of fish
Get stuck in a loop
Unlock a bonus level
Get your head in the clouds