If you re interested in this game, for sure you have played Halo 3 and maybe the previous games. Well, Halo 3 ODST is the side story of Halo 3, but with improved graphics, and a much improved multiplayer system. Its a half way between Halo 3 and Halo: Reach.
The single player campaign may be a little short but worth the playing! And the multiplayer is so awesome!!!
You will find more detailed reviews about this product, some say its a great game (and I agree with them) and others will say its more of a mission pack than a full game (sorry, but I find those a bit unfair). All I will say is that is an improvement over Halo 3 (not better, not worst, just different) and the only way you'll find if its worth the buying is playing it. But if you are a Halo fan, this is a must have. And if you like shooters, and never played Halo bejore, start with Halo 3, and then you'll find you need to try also ODST, trust me.
In overall, another game to include in the XBox 360 must-have list...