From Halopedia, the Halo wiki
Crewman 1 is a generic name for an unnamed voice part for a UNSC naval crewman in Halo: Combat Evolved. The title has since become a running joke at Bungie Studios' website, Bungie.net.
"They're right behind us!" is the only line of Crewman 1, voiced by Matt Soell, left in the game. There were other lines, but in the words of Martin O'Donnell, there was "no space on the disc for a guy with no discernible acting skills and a singing voice like a mule in a garbage truck."
Crewman 1 spin-off
Initially thought of as a joke, Marty spoke of creating a game around Crewman 1:
- There were also a few odds and ends of other crewmen or soldiers done by various Bungie actors but none had that "stand out" quality of Crewman 1. We're thinking of doing an entirely new game, a prequel, that traces the childhood and heroic life of Crewman 1 prior to his tragic and premature demise in Halo, starring of course the voice of Matt Soell. As a matter of fact - did Crewman 1 really die? Hmmm.....
On Sept 16, 2006, Martin O'Donnell continued the joke by claiming that something was in the works for a Crewman 1 video game, saying Screenshots soon ™