The latest ViDoc (video documentary) -- titled "Terra Incognita" -- for Halo 3: ODST, features the team that is Bungie talking about how Halo 3: ODST started off as a piece of downloadable content, like a "2-3 hour mini-campaign", and then transformed into something bigger, a full retail game.
Describing the game, CJ Cowan breaks it down, "Here's an engine, here's a story. You got a year. Go." Though don't let that description make you think this is merely an overpriced expansion. Bungie shares in the video how much work was put into the game to make it feel like a new experience. From the game's new weapons, new art style, and some of the new tech used to enhance the game play; all of this things led to making the game evolve into a full game.
