Starcraft II in beta and Command and Conquer 4 about to drop, here comes the Supreme Commander 2 demo, now available for download over on Steam. The demo features 4GB (!) of complex Gas Powered Games RTS goodness, in which you'll be able to try two levels of the tutorial, as well as play through two missions as the United Earth Federation faction. You'll also get to see some of those new units at work, and, we presume, do some supreme commanding. No peerless or incomparable commanders here -- supreme only!
One of those new units you can try out is a sea-based experimental submarine for the Cybran faction that's modeled and named after a legendary sea monster. So what are you waiting for? Go download the demo and get kraken!