Here is the full list of all 26 We Sing Pop achievements worth 1,000 gamerscore.
You need to play Versus for the first time
You need to sing your first song
You need to sing your first karaoke song
You need to sing your first instrumental song
You need to play We Sing for the first time
You need to score over 25000
You need to play Pass the Mic for the first time
You need to sing in Expert mode for the first time
You need to play Versus mode at least 10 times
You need to play Group Battle mode at least 10 times
You need to play Pass the Mic at least 10 times
You need to sing 10 songs with the instrumental track options
You need to score over 50000
You need to play We Sing mode at least 10 times
You need to end a song with less than 10000 points
You need to score over 25000 in 15 songs
You need to sing every song on the disc
You need to play Versus mode at least 20 times
You need to play Single player mode on Expert at least 10 times
You need to play Karaoke Mode at least 10 times
You need to score over 50000 in all songs
You need to sing 20 songs on Expert
You need to score over 90000
You need to sing all songs on Expert
You need to sing 1 song at least 50 times
Win in versus mode 30 times