Shoot 'em up

Subgenre of action game

Shoot 'em ups (also known as shmups or, chiefly in Japan, STGs) are a subgenre of action games. There is no consensus as to which design elements compose a shoot 'em up; some restrict the definition to games featuring spacecraft and certain types of character movement, while others allow a broader definition including characters on foot and a variety of perspectives. The genre's roots can be traced back to earlier shooting games, including target shooting electro-mechanical games of the mid-20th-century, but did not receive a video game release until Spacewar!

From Wikipedia, under CC BY-SA. More on occurri.