Coelocanth: Updates only available through Impulse. Welcome to Stardock's "We don't use DRM on our games" DRM.
Gersen: Yeah the good old "We don't use any DRM on the retail version of our games..................... but as soon as you ever update the game an online activation DRM will be installed forcing you to reactivate you game online should you change your hardware will be installed" DRM
That's actually not true. At all. They do require use of a registered Impulse account to update the game, but there's no really activation, and you can freely change your hardware, install it on multiple computers, and so forth. You don't need a constant internet connection, and don't have to download the update on the same computer where it's installed. This is a form of DRM, I suppose, but it's minimally intrusive, which is the whole point. If you don't like it, don't get the update. The game itself will still run, although unfortunately the box release was very, very buggy. Future sequals of the game will only be purchaseable on Impulse in the first place, so everyone who gets it will have an account already anyhow.
I'm a big fan of impulse by the way.