Microsoft's getting pretty good at not announcing Halo games. Not only did it not announce a new Bungie one at E3, but within the very same conference it managed to overlook Halo Wars completely. Given that Ensemble Studios' ambitious spin-off strategy game for Xbox 360 was announced in 2006, that raises serious questions about how long we'll have to wait to play it.
Ensemble was dodging those at E3, but despite the conference no-show it was actually demonstrating Halo Wars in a room upstairs, and even letting people like us sit down and play it, giving us our first chance to see how Microsoft's professed intent to "explore, not exploit" the Halo universe is unfolding in practical terms.
Expanding the Halo fiction isn't much of a problem for Ensemble - Bungie has a Halo bible that deals with years and years of events outside the scope of the three-game FPS arc - and Halo Wars drills 20 years into the back-story. But how the fiction actually expands is another question. The game follows the UNSC's discovery of a Forerunner artefact and their clashes with the Covenant over it, but apart from the scenario and timeline we're still in the dark. We're also not sure whether there'll be a Covenant campaign: Ensemble hasn't publicly ruled it out, only confirming that you will be able to play as the Covenant in one-off skirmish games away from the campaign. And now there are rumours of the Flood.
Whatever binds things together, though, those events will be fast-paced, brutal and very much in love with the things that made Halo so popular. Taking control of a UNSC force with a small base in the corner of a very Halo-esque environment, we're able to quickly pump out Marines, Flamethrower units (new to the series), Warthogs and of course Spartans - the Master Chief's contemporaries, who are out in force 20 years in the past - and assault a Covenant base on the other side of the map.
To get this to work fluidly, Ensemble had to do what nobody else working in the fledgling console RTS market has done and come up with a flexible, comfortable and intuitive control system. The team's answer is in multiple parts, but none is hard to grasp: you move a cursor across the map using the left stick, hover over a unit and press the A button to select it. Double-tapping A selects all the units of that type in your army, and holding down A allows you to drag a circular "paintbrush" selector around the map, which adds any units it touches to your selected group. Taking the fight to your enemies is equally simple: select some of your units, hover over an enemy and press X for your basic attack and Y for a special ability.
The base-building side of the game is also designed to be quick and easy to get into. It has to be: the base is the heart of your army, and if you lose all your bases it's Game Over. Starting with a grid of metal panels laid down by your orbital support vessel the Spirit of Fire (a colleague of the Pillar of Autumn, apparently - they met at the Christmas party), you select a panel and click on it to bring up a circular menu that has up to eight building options on it, allowing you to lay down a Barracks.