Do you remember the console? or was it a pc game?At this point. I've pretty much gave up, but I'll try. Memories of that game are very vague but here's what I remember.
Low polly graphics like characters from FF7. Black sky. Scenery is grayish chrome buildings. It's action/platformer/slasher. And the thing I remember the best is that character dual wields swords and in that demo you can find some other sword that you can equip. I found this game on a disc from a gaming magazine somewhere back in 2004.