Most of the original music was composed by Martin O'Donnell and Michael Salvatori, but also includes a bonus track, "LvUrFR3NZ", which was the winning entry in a contest held before the soundtrack's release.

For the next game in the Halo trilogy, O'Donnell added new themes as well as bringing back and expanding old ones, some of which had never been recorded with a full orchestra before.

The score made extensive use of the piano, an instrument which O'Donnell used frequently for composition but that had not been featured in previous Halo music.

The score for Halo 3 gave O'Donnell and Salvatori a chance to rework and revise existing themes heard in the games, as well as create new ones.

'"[3] He intentionally made the score to the final game a shift back to the orchestral roots of the series, stating "I took an orthodox, almost formal approach to the trilogy.

"[3] O'Donnell acknowledged that some games and movies used entirely different music with each sequel, but such an approach wasn't an option with Halo 3, the third installment of a trilogy: "The Master Chief is still green, Cortana is still blue, and so you're going to hear the monks and the cellos.

"[4] O'Donnell began by writing out the reworked themes and music he wanted to hear in the game, without knowing where he would eventually use the sounds.

[5] O'Donnell designed the opening to lull the listener into a sense of suspense, then wonder; "I want them to feel pride and longing the moment Master Chief walks out of the smoke."

[17] In addition to the music composed by O'Donnell and Salvatori, the announcement of the Halo 3 Soundtrack was followed with a call for entries to all artists or bands to submit their own original song to be included on the final CD.

"[22] Conversely, IGN found the piano theme was perennially overplayed, and felt that the soundtrack "begins with a bit of a bang and then eventually sputters out".

[31] Arrangements featuring music from Halo 3 appears on the album releases Video Games Live, Vol.