You have a endless mode, play until you loss.
I mean an adventure mode, something like Puyo pop, or Robotnick Bean mean machine were there is a simply history that tie a serie of finite chalenges, basically a excuse to add wacky animations or small comics strips were you could explore the alien personality
Something pretty standard in several puzzle games of handeld and retro consoles
Sometimes it's no more that a camuflaged and glorified tutorial, something pretty common in games focus in the multiplayer.