Throwing in a quick tip for those who, got the game for free, want to make the first 4 minutes a breeze:
Go to one of the corners, pick Echo Echo (tiny white guy), set up the three duplications, switch between them to spread them evenly on the platform.(Far left, far right, middle)
Make sure you are in control of the far left(or right if you picked the right corner) copy to prevent the aerial enemy from firing at you in this form.
Keep punching until the last type of foe appears at the four minute mark.
Switch to Humungousaur and alter between killing(including the previously ignored aerial one) for the last minute to gain the achievement.
Last edited by Mantle; 09-03-2013 at 11:42 AM.