Walk-Off Winner

Walk-Off Winner is an Achievement in Halo Wars that is unlocked when the player uses one of the 6 Major Leader Powers to destroy an enemy's last unit.

It is worth 30 Gamerscore.

Tips
Go on the advanced tutorial, then, when you are in control of Regret, move the s away and then kill all of the enemy units outside of the UNSC base.

Play on Release and release the Flood, and then use a leader power to destroy them all.

Play a 1 vs 1 with a friend and get him to buy no units, then use a leader power on his scout unit.

The achievement can also be earned on the campaign level "Scarab" by killing the scarab with a MAC blast.

Trivia

 * The name is a reference to a "walk-off home run" in baseball, in which a batter hits a home run in the bottom of the ninth inning or later, and in doing so adds enough runs to their score to win the game. As a result, both teams "walk off" the field once the winning run is scored.
 * Even though the title says an "Enemy's last unit" you can actually get it by killing an ally's last unit with Regret's cleansing beam.