If Halo 4 is a bust, it won't be for lack of trying. Microsoft Studios head Phil Spencer told Polygon that the company has spent more money making Halo 4 than it has developing any other game in the company's history.

"Absolutely. Nothing's even close," he said.

Spencer added that the Halo series, which he estimated to be a three billion dollar franchise, is the company's "most important entertainment product." Some of Microsoft's other major franchises include Forza, Fable, and Banjo-Kazooie.

Halo 4 is due exclusively for Xbox 360 on November 6 worldwide. The game is a direct sequel to 2007's Halo 3 and is the first numbered entry in the series developed outside of Bungie Studios. It is the first installment in the Reclaimer Trilogy, which will span Halo 5 and Halo 6.

A recent Nielsen study found Halo 4 to be the most anticipated holiday 2012 title for Xbox 360 owners.