Here is the full list of all 8 Melody's Escape achievements. It takes around 5-6 hours to unlock all of the achievements on Windows.
Score 5 hearts on a track in any difficulty
Score at least 3 hearts in any difficulty
Play one track
Get a Perfect Chain Score in any difficulty
Get a perfect Chain Score in Intense difficulty
Play 10 tracks
Play 100 tracks
Get a Perfect Chain Score in Intense difficulty 10 times