How long does the Darksiders game take to install?

I just got this game, opened the setup and it started installing. It's still at the "extracting files" stage and it's been longer then an hour, I think about two hours or so. When I look at the free space of the hdd it keeps adding and removing free space (mostly removing as the folder grows). Just how long is this game's installment supposed to take? I know Mass Effect 2 (which has quite an imposing size) took a lot less, so what's the deal with this game taking so long?|||j