Here is the full list of all 37 Let's Sing 2016 achievements.
Accumulate 500 VoxPoints
Finish 90 songs
Get a score over 100,000 points
Sing all the songs
Pass the mic 30 times in Pass the mic mode
View all the credits
Listen to 10 songs in a row in Jukebox mode
Get 500 'PERFECT'
Finish 40 songs
Accumulate 100 VoxPoints
Finish a song in 20,000! mode in under 60 seconds
Hit all the golden notes in a song
Finish with a similar score to your partner in Duet mode
Finish 5 songs without the vocals
Finish 15 songs in a session
Finish a song in Expert mode without the vocals
Get a score over 80,000 points
Start Expert mode
Start Elimination mode
Unlock all the game modes for a song
Start 20,000! mode
Start Duet mode
Sing 3 songs in a row from before 2008
Accumulate 50 VoxPoints
Get a score between 50,000 and 51,000 points
Get a score inferior to one point
Sing 5 songs in a row released after 2013
Start Pass the mic mode
Start By Heart mode
Finish a song
Browse through the song covers 3 times in less than 20 seconds
Get a score over 120,000 points
Finish a song in Elimination mode
Get 10 'PERFECT' in a row in Expert mode
Get 'PERFECT' for the parts of a song with no lyrics in By Heart mode
Finish 150 songs
Unlock all the game modes for all songs