Just Dance 3

To get this achievement, you need to obtain at least 4 Stars (8,000 Points) on every song in the game (excluding mashups & extra dances).

Set the player difficulty to 'Easy' before you dance to the songs to only register your upper body movement, this'll make things easier getting the four stars on each song.

This'll also unlock the bronze variation (3 Stars on every song) of this achievement & you can then push for the Gold variation (5 Stars on every song)!