Games don't need stories.

[Mr. sickVisionz]

It's comparable to a song without lyrics. You have to really hit it out of the park to make that work. A game with no story needs to be like old school mario or sonic: by design, you will never be bored at any one part and the the stages are pretty short (10 minutes or less).

With no story, it's 100% gameplay that motivates the player to keep playing. If that gameplay ever falters, you have nothing to fall back on to keep the player moving forward.