The most obvious new feature is the new single player campaign with ten new missions, many in new locations in the Mediterranean and Eastern Europe. These missions also include improved artificial intelligence for the bad guys (including the ability to call for back-up and use hostages as human shields) and there's a new split-screen co-operative mode that allows you to team up with a friend and two computer team mates.
Perhaps the most important additions though are in the online multiplayer mode, where Black Arrow will be one of the first games to utilise new Xbox Live 3.0 features such as user-created tournaments, instant messaging and clan statistics. Add in two new objective-based game modes, in the form of "capture the point" and "capture the flag", as well as new private team lobbies that see a return of sorts for the original Rainbow Six pre-mission planning interface, and you've got more new features than you find in most full-blown sequels. Which is far more than can be said for most similarly priced PC mission discs. --David Jenkins