Warlords

This is the "cheese" method to get this achievement. It makes it very simple, In fact most have this accidentally happen anyway.

What you want to do is take out the top left guy, or the bottom right guy first. It really doesn't matter which one you choose. You want to tap A for the powershot to destroy the opponent's walls instead of holding A, it will take 2 shots to completely destroy his wall.

How to perform the glitch

This is very simple, yet mostly luck at the same time. After you send the killing shot you want to bounce the ball back, DO NOT powershoot it back. If it goes straight (which it rarely does, hence the luck factor) it should hit the new spawning ball. This will glitch the new ball and give it the ability to pass through walls. It will go into the diagnol's guy wall hopefully, thus giving you an easy kill.

A bonus is if it kills the other guy you didn't kill before. If not then use the powershot method on the other guy.

Here is a video of me performing this glitch