Half-life 3 Confirmed. It will be where the Covenant and Black Mesa are in a battle for the Earth (they discover that the Earth has 10x the power of a halo ring explosion and could destroy all the verses), and the humans accidentally activate the device for 10 seconds in which a parallel universe opens up and Samus steps through right before the crack in space/time closes. She then is enlisted in and helps save the Earth from both the Black Mesa and the Covenant until... at the very end... they discover she isn't from a parallel universe, but the past. She is... a Forerunner. And that's how the game ends...