MBO pointed out an unusual Gamasutra postmortem article from last summer which I don't remember seeing before. It's not on a game itself, but of an update to a game. In this case, the 1.5 and 1.5.1 updates to Myth II produced by Project Magma. It's a two-parter; one details what went right and the other what went wrong. Don't know what Myth is? Head to Get Myth and get the updated demo for Windows or Mac OS X.