Ruby on Rails, often shortened to Rails, is an open source full-stack web application framework for the Ruby programming language. Ruby on Rails is not to be confused with Ruby, which is a general-purpose programming language, on which Ruby on Rails runs. Ruby itself existed for more than 10 years before the first release of Ruby on Rails. Rails is a full-stack framework, meaning that it gives the Web developer the full ability to gather information from the web server, talking to or querying the database, and template rendering out of the box. As a result, Rails features a routing system that is independent of the Web server.

David Heinemeier Hansson extracted Ruby on Rails from his work on Basecamp, a project management tool by 37signals (now a web application company). Hansson first released Rails as open source in July 2004, but did not share commit rights to the project until February 2005. In August 2006, the framework reached a milestone when Apple announced that it would ship Ruby on Rails with Mac OS X v10.5 "Leopard", which was released in October 2007.

Shoot 'em up (also known as shmup or STG) is a subgenre of shooter video games. In a shoot 'em up, the player controls a lone character, often in a spacecraft or aircraft, shooting large numbers of enemies while dodging their attacks. The genre in turn encompasses various types or subgenres and critics differ on exactly what design elements constitute a shoot 'em up. Some restrict the definition to games featuring spacecraft and certain types of character movement; others allow a broader definition including characters on foot and a variety of perspectives. Shoot 'em ups call for fast reactions and for the player to memorise levels and enemy attack patterns. Newer "bullet hell" games feature overwhelming numbers of enemy projectiles.

The genre's origins can be traced back to Spacewar!, one of the very earliest computer games, developed in 1961 and eventually released in arcades in the early 1970s. However, Space Invaders, released in Japanese arcades in 1978, is generally credited with inventing and popularising the genre proper. Shoot 'em ups were popular throughout the 1980s and early 1990s as they evolved. From the mid-1990s and the burgeoning use of 3D graphics in video games, shoot 'em ups became a niche genre based on design conventions established in the 1980s and increasingly catered to specialist enthusiasts, particularly in Japan.