According to a report on The Inquirer this morning, the Doom movie has undergone some totally bodacious plot rewrites which I am sure every Doom fan is going to just love. Says them:
The changes? Well, Doom won't be set on Mars. The monsters have nothing to do with Hell. Space marines are SWAT teams. The monsters will, apparently, be people mututated by a secret virus.
I know, cool huh? Remember though, this is the The Inquirer, they're not exactly above, well, lying.
EDIT by Bloodshedder: You might want to take a look at the report they're referring to, even if it's not in English.