The game was one of the first to break out of arcades and milk bars and into the consciousness of non-gamers. A little lesser-known, but Konami fans should give the Thunder Cross titles a spin. Whenever someone brings up Konami shooters, talk inevitably centres around Gradius / Salamander / Parodius, but there two are up there with them. @glympe I'

The genre's roots can be traced back to earlier shooting games, including target shooting electro-mechanical games of the mid-20th-century and the early mainframe game Spacewar! The shoot 'em up genre was established by the hit arcade game Space Invaders, which popularised and set the general template for the genre in 1978, and spawned many clones.