Prepare to Drop - Into Halo 3.2
Halo 3: ODST is a side story in the Halo universe about a small squad of ODSTs that drop into the city of New Mombasa that exists somewhere in Africa. This title is intended to have a fundamentally different feel from the core Halo games, since the Master Chief is nowhere to be seen, and you take control of "ordinary humans" in the fight across the city. Thematically, this works well. The storyline is based on a group of people, rather than focusing on the one man army that is the Master Chief, as they accomplish relatively small tasks in a fairly limited area. Contrasted to the huge scope of the core Halo games, ODST certainly has a different flavor to it, especially in the pseudo open world nightime portions where you play as the lone Rookie looking for his comrades.
However, if you are looking for any significant changes to gameplay, you will find this game lacking. Virtually everything about the game mechanics is exactly the same as Halo 3 - you can still hijack enemy vehicles, jump llke Super Mario, and beat the living hell out of stuff with your bare hands. The only noticeable differences are the lack of dual wielding and equipment (such as the bubble shield), and the fact that you take fall damage. It just feels odd to me that you can grapple the back of a Covenant tank and punch it to death in seconds, but aren't quite capable of holding two guns or throwing down a bubble shield. Another difference is that ODSTs do not have shields like Master Chief. Unfortunately, that chance for a real gameplay difference is squandered by the all new mind blowing invention of "stamina", which protects you from damage up to a set amount and recharges if you avoid getting hit for a few seconds. Sound like shields? It is.
Some new features add a bit of ODST flavor, although limited. These include your VISR, which is essentially night vision, and the inclusion of a map of the city for your roaming purposes. The VISR is extremely helpful through much of the game, but the map is only sometimes helpful, and feels sort of like a tacked on way to make it seem more "open world" when the game really is about as linear as any Halo game. Oh, and if you stop to open your map, make sure you're alone, because it doesn't pause the game.
ODST is about the standard FPS length (6 or 7 hours) and includes one new mode called Firefight. Firefight is a co-op based survival style mode where you fend of waves of Covenant troops of increasing difficulty for as long as you can. This can be alot of fun, and can really suck you in if you have friends to play with. Unfortunately the fairly short campaign and firefight are the only things new about ODST, a problem the developers must have noticed because they include with your purchase the complete Halo 3 multiplayer, with every DLC map already available as well as 3 new maps. Maybe that is a meaningful add on, but I suspect that if you cared about that then you would already have Halo 3 and all the maps.
In the end, ODST expands the Halo franchise in some ways, but really is just that: an expansion - not a new experience. I would urge anyone looking to purchase this game to consider the $60 price tag and ask if thats really worth it for something you've either already seen, or, if you haven't, must not have had an interest in to begin with.