I always link musical sources in the credits - but here they are, all in one place.
Most music is from the "Newgrounds Audio Portal".

Menu music: "War Drums" by BokutoMasamune

Intro music and ending music: "StringMix" by KlausKing

Main music during movie: "The Sands of Time" by Evil-Dog

Main music during movie: "Second Awakening" by Evil-Dog

End music and credits: "Blessing" by Evil-Dog

Crappy menu music: Not named, by me, and unavailable.

Intro music: Unknown source.

In-game music: "Lost in Space" by SBB

Intro and menu music: "Redemption of the Beast" by XGM_Zeth

In-game music: "Dual Action" by Anth0n

Overly dramatic menu music: "The Matrix" by ss_ gogetanks

In game music: "Arctic Death Platoon Theme" by Ryanitto

Boss battle music: It seems to have been removed from Newgrounds, or I just can't find it.

Menu Music: "World Killer" by Whack-a-mole

Game music: "Creeping" by Cypher_

Looping menu music: "On a tide, under the moon" by Ghostmachine

Game music: "Golem War : Battle" by Evil-Dog

Weird space-soundy music thing in intro: Unkown source. From some "free loops" site.

Menu music: "The Wizard" by Evil-Dog

Intro and "you loose" music: "Death" by Evil-Dog

In game music: "Close Combat" by ParagonX9

Unknown sources.

Not named, by me, and unavailable.

The only music in the movie: "Du Hast" by Rammstein

Awesome introductory music: "Over The Mountaintop" by cycerin

Awesome "ambulance music": "Boss Song (Theme from a game)" by i1011i

Awesome tense hospital music: "The Enemy Draws Near" by mattcalpo

Menu and credits music: "Activate..." by BokutoMasamune

Movie music: "LG Orbifold" A.K.A. "HL2_song16" from the awesome game "Half Life 2" which everyone knows already. You need a program called "GCF scape" or something to access it if you have Half Life 2.

"Battle music" at the end: Uhhh... can't remember...

Intro and credits music: "Data Surge" by NemesisTheory