Steam then implies I have to download shogun 2. The whole freaking game!!??! Its not saying update here either BTW. It also doesnt tell you the size of the download either so I cant even really determine if it is indeed trying to download the whole game.
You can see how much/size is being downloaded.
When the game is downloading files when your logged on to Steam...select Library..Downloads.
The screen that shows the download will show you....how big the download is, when the download was started, what speed you are downloading at and how much time is left to complete it.