Ruined endings - part one

Gears of War

It's your classic war scenario - a guy with a smashed in face is on a train carrying an underwater missile launcher and is rapidly approaching a broken bridge. He heroically jumps to a helicopter, the train crashes into the water, and the torpedoes launch, decimating the alien stronghold. But then some alien thing is like, "Whatever, you totally didn't kill me, so there's going to be a Gears of War 2 because Cliffy B needs more bitches."