Eat Lead: The Return of Matt Hazard

When you get maximum hazard (you turn red) melee as many enemies as you can. They will go down with one hit. Once you kill melee 10 enemies with one hit you will get this. It is cumulative.

I found this to be easiest on Dexters mansion mission. When you shoot Dexters Darlings they shut down for a short period of time. then if you melee them while they are shut down it only takes one hit to kill them.

you can all so do it by shooting the lady robots when they short out and bend over just run up to them and pressing x after u done 10 up pops the achievement.

I got this achievement during Level 4, Backdoor Assault at the Big House.

After clearing the Guest house of all enemies, you will run up some stairs to continue the mission and eventually enter a tennis court area. This is where the game first introduces you to Zombies.

Numerous Zombies will spawn as well as 3 Russian soldiers. Kill the gun-wielding Russian soldiers and run to the centre of the tennis court to collect the Hazard pickup.

Now all you have to do is run up to each Zombie, one at a time, and press X to instantly kill them. Repeat 9 more times for the achievement to unlock.

I also used this method to unlock the Feeling Punchy achievement.

Please comment if you vote negatively. I will edit my solution to make it better.