Published on May 30, 2010 The easiest way to get this achievement is to play the final mission "End Game" in Single Player Campaign and select mode "Recruit". Jump into the boat and hold the RT (Right Trigger) to accelerate the boat and the LT (Left Trigger) to shoot your weapon. Go full blast until you reach the bit with all the boats in front of you.. This is where you will have your chance to kill over 20 enemies while driving a vehicle (boat)..