A dash of tower defense — During gameplay credits can be earned by performing acts such as melee kills, repairs, and control point captures. (xblafans.com)
Now instead of just from your sniper rifle, you can see them from melee kills and trap kills. (dailyjoystickpodcast.com)
And since we're on the topic of melee kills: what happened to knocking people out with the butt of your gun? (kotaku.com)