Here is the full list of all 11 Ephemerid: A Musical Adventure achievements.
Unlock The Secret Game. Use 'F' and 'J' on the keyboard, or left and right triggers on an XBox controller
Complete all rhythm tap and flick scenes without missing a beat
Squeeze past the snail without putting it in a bubble
Play the melody to Kung Fu Fighting
Brush the title scene leaves into a nice little pile
Favor saving either bees or beetles from the spider
Start any scene on slow
Help a simple mayfly make its one day on earth spectacular
Make it all the way to the end of the secret game
Make it all the way to the end of the secret game playing on slow
Woah, you just did that