A Cobra Strike

"Suddenly, a cobra strike - a classic game move, MASTER CHIEF strikes with the butt of his assault rifle, taking out ELITE's shields...

... and as the ELITE staggers back, MASTER CHIEF empties half a clip into the alien's torso.

Thirty rounds fly through the gun in two seconds."

For those keen on detail, some things of note here: although described as a "classic game move" it's unclear whether they mean Halo in specific or just games in general. A melee hit from behind such as this in Halo is usually a one-hit kill, so emptying half a clip would have been unnecessary. However, while that works as a game mechanic, it might well have strained credulity on the big screen, so this may be a positive change.

Also, thirty rounds is half a clip, at least for Halo 1's assault rifle.