Doom the Movie

Why oh why did they have to butcher the central point of the games story line?

The movie is alright in as far as it is a little like aliens and it does a few nods to the game particuarly the scene which is basically just like playin he game BUT to be a doom movie you MUST have demons! You cant have some other tacky excuse for why somthing od is wandering around. Doom is supposed to be about the man too tough for hell.
Furthermore it is ok to build up the suspense but the main part of the movie should be hack and splater regarding many different types of monster - Come on thats why people bought the game!
AND I really dont think you can do it justice without lord of the rings level computer animation etc can you imagine a scene like in "the one" with a million demons coming up to fight a soldier on a hill top?
I expect someone will now destroy my faith in hollywood by doing foundation (the whole series in one movie) without any special effects and no robots or psycics and the mule just being a nasty fellow.