Ben 10 Omniverse

The way i did this was by playing the tutorial on easy amd just using four arms to do my attacks. Play it safe dont get too near any edges when attacking incase you fall off. transform as much as possible and stay as four arms as much as you can. If you get knocked out of it just do like i did a run around for a little while away from the oponent until you can transform again then go back in for the attack. When you get a chance to level up do so with four arms so you can start to drop rocks on multiple enemies at once which makes things so much easier. Use the same tactic against the giant ant and you will have this achievement in no time...just wath the gap when jumping.