Halo 3: Recon is partly a product of Bungie's sorta-kinda split with Microsoft. So says Bungie.

Speaking in an interview, Bungie writer Luke Smith said of the game, “It's also a product of our schism from Microsoft; where now, one of our core tenets as we left Microsoft is to be a multiproject studio that's able to focus on new IP. So as we begin to focus on new IP, and we have multiple projects spin up at once, [the idea of] meeting our fan desire for more Halo 3 content, and doing it with a team of incredibly grizzled veterans at Bungie, made perfect sense to us.”

Translation: if Microsoft were still the boss of Bungie, it would have the whole studio plugging away at one new game and it wouldn't be an expansion.

Of the game itself, Brian Jarrard (community and PR director for Bungie) was keen to point out, “We're not bullet-pointing the sandbox, but keep in mind that it's a pretty short development cycle. We are just trying to build on top of Halo 3.

“I wouldn't expect to see the equivalent of adding the Brute sandbox in Halo 3, where it's a whole suite of weapons and vehicles attributed to a single race; that was just a much bigger scope project that we're not trying to do in Recon. There might be things that are specific and contextual to playing as the ODST, but I can't really detail those out today.” That's what's known in corporate circles as 'managing expectations'.

Bungie split from Microsoft last year, but has remained exclusive to the platform holder.

You can find more on Halo 3: Recon here.