Mombasa Streets

Mombasa Streets is the first campaign level of Halo 3: ODST, and an open-world environment known as "hub world".

Summary
This level is a freely explorable open world environment, which contains "beacons", clues to the fates of other squad members, which trigger "flashback" levels. The player can freely choose the order the flashback missions are played in, although there is a certain preferred order, as stated by Bungie.

Plot
The level starts six hours after the Squad's failed orbital insertion, in the occupied city centre of New Mombasa. Some time after the Rookie wakes up, exits his pod and starts to explore the city, the Superintendent will contact him via a public phone and upload a map of the city to his VISR navigation database.

The map shows points of interest, such as "beacons" of the Rookie's Squad mates, which trigger additional flashback missions. The Superintendent will also guide the player into the right direction using the city's plentiful digital signs and billboards.

Trivia

 * This level marks the return of the Brute Plasma Rifle.
 * This level is the only level in Halo 3: ODST which does not unlock an achievement upon beaten on normal or above. This is probably because of the fact that this is a free roaming level.
 * This is the first level where you play as the Rookie.
 * This is the first non-linear open-world level ever in a Halo game, and the largest open environment Bungie has ever created.
 * The level's moody atmosphere, from color palette to lighting and music, is said to be influenced by the Film Noir genre.