Okay, I admit it. After the announcement of Halo: Reach, set to come out in 2010, only twelve months or so after this year's Halo 3: ODST, I was set to bash Bungie for being unoriginal and Microsoft for upping the production quota on the goose that laid the golden egg(s).
I had a piece all written, with a pleasantly unpleasant pun in the title, about how this was only to be expected; that Microsoft almost certainly extorted... I mean, exacted from Bungie a promise to continue on with at least X more Halo titles after receiving their independence. This would appear to be true for all situations where X is two or larger. Originally I had thought perhaps ODST would be it; that was probably naive of me.
Of course there's always every chance that there are people in Bungie who want to continue with Halo. Just like Id software nearly split in half over the decision of whether or not to revisit Doom with Doom 3, one might imagine that some old-time Bungie devs want to go back to doing a game and a sequel and let the spinoff studios handle the third game, a la Marathon and Myth. It also seems possible, though, that there are Bungie devs who have not worked on anything but Halo, and perhaps some of those want to keep doing it because they like it, and others want to do something else because they're tired of it.
ODST, I figured, would be an expansion pack: some new campaign and multiplayer levels to tide us over while Bungie works on the Next Big Thing. In some ways, perhaps that's true. However it also looks like we're getting a lot more out of ODST than just that, and the design team have made some intriguing choices, many of which were on display at E3.