The game is set in New Mombasa, the futuristic city introduced in Halo 2, where your squad has ended up spread out across the Covenant-infested streets after its mission went pear-shaped. The story tracks the troops' attempts to regroup with players switching back and forth between soldiers much like the to-ing and fro-ing between Master Chief and The Arbiter in Halo 2.
The main difference between Halo 3: ODST and the series proper is in perspective. As Master Chief, the player went on the offensive, charging into battle. But this time around the player is the hunted rather than hunter, fighting to stave off swarms of aliens while desperately seeking an escape route. It's a change reflected in the soundtrack that replaces the bombastic score of the main Halo games with a more muted jazz soundtrack.
Yet beyond these changes it's largely business as usual: battles with alien troops peppered with chances to take control of vehicles and memorable firefights. The one big disappointment is how lifeless New Mombasa is. Beyond a few upturned or burnt out vehicles and some audiotapes of one citizen's experience of the invasion, there's little to suggest the game is set in a once-thriving city now under alien control.
Despite this Halo 3: ODST is a decent enough spin-off, providing a worthy fix for Halo fans keenly awaiting a proper follow-up to Halo 3. Solid, but rarely surprising.
Halo 3 ODST - Official Trailer