The demo is a 3 hour trial version which comes with a launcher. That launcher requires Microsoft .NET 2.0 to be installed on your computer. If it is not installed, it will see if it can download this from Microsoft and install it. And internet connection is also required the FIRST time you start the game (which will give your copy a unique ID). After that you can quit and start as often as you want offline, but after 3 hours the game will terminated.