This achievement is earned after you win a flag attack game on all 12 maps.
Set the difficulty to easy with a score limit of 10. The fastest way to finish and win is by capturing 4 flags at once, when you cap 4 at once you earn 10 points and instantly win the game. Some games I was winning in under 45 seconds, the longest was 3 and a half minutes. Capturing 1 flag earns you 1 point, 2 flags earns you 3 points , 3 flags earns you 6 points and 4 earns you 10 points. Just go for any flag you see, if a enemy has one then smack him or boost into him to steal their flag, if they smack into you or hit you they can take your flag aswell. Once you have 4 flags return them to the goal and you get the win. Repeat on all levels and the achievement is yours!