The game has gone through 4 years, and +200 updates since it came out (and no signs of stopping!), so I think that for the time it's been existing, its 10 GB size is sort of justified. In my respective opinion, that is.
Of course, been a player since '08, and ever-loyal to the franchise, so I'd guess I'd be a bit biased anyway...
And Sinner, I'm pretty sure it doesn't cost a thing to make a Steam account... just go on the
Steam Store, and click "Install Steam." The install process should give you the opportunity to make an account while you're at it as well.
Oh, and that video is pure gold