It's basically a pick-a-path style story on a DVD.
Scourge of Worlds (SOW) is a strange DVD. It's basically a pick-a-path style story on a DVD. The story plays out and every once in a while you make a decision. There appear to be 23 potential decisions, you'll see about 8 per game. The game claims that there are over 990 potential combinations, my calculations suggest there are 757 actual possible paths. I'm not sure how they came to the 990 count. Technically there is nothing especially noteworthy about SOW, DVDn as they term it is just a fancy name for using the existing DVD menuing system to create a pick-a-path story.
The publisher has disabled chapter skipping and a great deal of functionality in an attempt to force you to stick to the official paths. If you'd like to jump directly to various tracks, I suggest getting a non-crippled DVD player. Some standard DVD players can be easily configured to remove this crippling behavior. Linux (and other Unix-like operating systems) have access to excellent software players like Xine and MPlayer that are not crippled. Note that if you jump around in the disk, you may skip important signals that control future events; you can view any part of the game you want, but the game may not work correctly until you start over from the beginning.