Perfect Dark Zero

Set up a 2 person local map and choose desert as the map and move the second controler to the street, have your main sitting in the street and attack the second controller. Melee from the front, from the back does not count.

Just get a total of 10 melee kills across all your games.
just walk up to an enemy and tap the "B" button with any weapon to preform a melee attack. Also the Sword counts as a melee kills so you can just hit right trigger when you have a sword equipped. You will unlock this achievement at the end of each game (not round)

NOTE:You can not obtain this achievement while in campaign mode