shoot 'em up

noun2

1. •
   A piece of media which depicts considerable gunplay.

   • My wife won't watch this movie; it's a shoot ’em up.
2. •
   A video game in which one plays as a character moving and shooting in an autoscrolling two-dimensional world, with emphasis on dodging bullets and predicting enemy movement patterns.

   • Bullet Hell: DoDonPachi exemplifies the term better than any other shoot 'em up, providing a snowstorm of fiery pixels to both simultaneously dodge and eliminate. — 2011