From the publisher's website:
Metropolis: Battle-force Conflicts
The war in Iskandria is escalating and the initial skirmishing is developing into full-blown military conflict. In response, all the warring factions are throwing in ever-increasing numbers of fresh troops, including heavier armoured elements and specialists.
With your Urban War strike-team as the core, Metropolis enables you to build much larger battle-forces to pit against your enemies in full-scale warfare.
Game Intro
Metropolis moves the action up a level from the small-scale skirmishes played out in Urban War. It shifts the focus from the individual to the squad. Your armies, or ‘Battle-forces’, will largely consist of several squads that vary in size, but normally contain around five to ten troopers. Accompanying them will be various individual models that represent important officers and characters, and larger more powerful war machines and vehicles.
Each faction has a different battle-force structure. Various basic squads form the foundation of their battle-forces, with the mix of support, assault, and elite squads, and the accompanying individuals and war machines, giving each their own unique flavour.