The charming video which you'll find just below the break is an expert blending of Halo 3 and Fallout 3 and it holds within it two very basic truths. One: It's fine for Fallout, but Halo probably wouldn't be better if it stopped every 10 seconds to let you select which body part to aim for.
The second truth? Apologies to Marty O'Donnell, but Halo would be much, much better if set to the melodious vocal stylings of Roy Brown. Sorry if that's hard for you to hear.