8/10. Has an epic feel to it. Reminded me of The Legend of Zelda: Twilight Princess at one point. Yeah, it was THAT epic. (In the less slang-like use of the word. "Heroic or grand in scale or character.")
Now, for my contribution:
This is the end-game music for Doom 2. Imagine it: the horrendous visage of the most immense demon you've ever seen crumbles to the ground. You've done it. Earth is saved, etcetera. Point is, you feel like a f***ing bad-ass after you complete this game, and the music really helps you get to that point. Hard to describe how epic it is. Just listen to it.