Warface had previously been available on Xbox 360 in beta. If you pariticpated in the beta, you don't need to re-download the game, as you need only download a title update the next time you play the game. Anything you purchased or earned in the beta will be available to you in the full game.
On Xbox 360, Warface requires an Xbox Live Gold ($60/year) subscription, so it's not exactly free. The game, built on CryEngine 3, features four soldier classes, as well as competitive and cooperative modes. In a bid to keep you engaged, Crytek also plans to release new missions on a daily basis.