Here is the full list of all 50 Just Dance 3 achievements worth 1,000 gamerscore.
Finished a song without missing a move
Finished a Duet with 2 players getting at least 4 stars on both choreographies
Finished a Duet with 2 players getting at least 3 stars on both choreographies
Played for 3 hours Between 8pm and 3am on a Saturday
Danced for more than 1 hour in Non-Stop Shuffle
Played 100 songs
Danced between Midnight and 4am
Danced every song in the "Songs" menu in a row while in the same game
Played every song in the "Songs" menu at least once
Played 50 songs
Earned 20,000 Sweat Points
Earned 10,000 Sweat Points
Got 5 stars in Simon Says
Played the same song five times in a row
Got 4 stars in Simon Says
Got 3 stars in Simon Says
Uploaded one of your own choreographies
Downloaded one Just Create choreography
Played one of your own choreographies
Created 50 choreographies in Just Create
Created 25 choreographies in Just Create
Created a choreography in Just Create
Got 1,000 Sweat Points between 5am and 9am
Earned 1,000 Sweat Points
Reached 250 Sweat Points with a 4-star rating on a song
Reached 150 Sweat Points with a 3-star rating on a song
Shouted Out at least once in a song
Finish any song in the "Songs" menu, and score "Good" or better on all moves
Finish any song in the "Songs" menu with at least 90% of "Perfect" moves
Finish any Dance Crew with all 4 players getting at least 3 stars (songs with 4 coaches)
Finish any Dance Crew with all 4 players getting at least 4 stars (songs with 4 coaches)
Finish any Dance Crew with all 4 players getting 5 stars (songs with 4 coaches)
Get 5 stars on 2 songs in a row from the "Songs" menu
Get 5 stars on 6 songs in a row from the "Songs" menu
Get 5 stars on 10 songs in a row from the "Songs" menu
Finish any Duet with 2 players getting 5 stars on both choreographies (songs with 2 coaches)
Get at least 3 stars on every choreography in the "Songs" menu
Get at least 4 stars on every choreography in the "Songs" menu
Get 5 stars on every choreography in the "Songs" menu
Reach 350 Sweat Points with a 5-star rating on any song with Sweat Mode activated
Get all Styles once (excluding Just Create)
Get four Dance Styles at the same time! (excluding Just Create)
Get all Styles with the same player during one game session! (excluding Just Create)
Play 200 songs (excluding Just Create)
Get 5 stars on any song after disabling pictograms in the Settings menu (excluding Just Create)
Get 5 stars on 5 songs in a row after disabling pictograms in Settings menu (excluding Just Create)
Get 5 stars on 10 songs in a row after disabling pictograms in Settings menu (excluding Just Create)
Shout Out at least once in 10 different songs
Shout Out at least once in 20 different songs
Get 4 Players to line up side by side from shortest to tallest while in the pre-game Lobby