Your character, Kurt Hectic, runs down all the aliens and then chases their leader, Gunter Glut, back to his home planet and kills him, probably after mocking him for being named Gunter Glut. Kindness has been delivered, and the world is saved! Or at least Hectic thought it was. Little did he know that he had doomed humanity to a fate worse than death.
The WTF Ending:
After free falling onto one final alien ship, Hectic realizes it isn't a war zone so much as an arena. And the headlining act is Billy Ze Kick, a French pop band whose biggest claim to fame is, well, this. They perform a rollicking little number called "Non, Non, Rien N'a Change," which translates to "What in the Name of Holy f**k Am I Staring At?"
And something about crepes, maybe?