A few years ago there was a trailer for a video game which showed a girl entering an apartment. The apartment felt "off" and then she had to fight some sort of monster. All in all, it was a pretty epic fight, but I was not sure which game that ended up being. There was a website, but I can't seem to find it.

This trailer? YouTube - The Secret World (Game Trailer) (http://www.youtube.com/watch?v=lsLXQEeLiI0) The Secret World, a MMORPG yet to be released.

Yeah it is Secret World. Supposedly its due to be released for PS3 I think.