The Steam version will now ask for the key on 3.0, actually -- this was sort of an oversight on my part, but it leads to a more unified binary and will hopefully cut down on confusion with new AI War customers through Steam, anyway (I got quite a few understandable questions about "Where do I enter the key it tells me I have to enter?"). So that's the base game key. But, the expansion requires a different key that is entered on the settings window if you do get that.