Shoot 'em up is a video game subgenre of shooting games. The common elements of shoot 'em up games are shooting at enemies while trying to dodge various obstacles and enemy fire. Sometimes the player is unable to move and other times the background will have a scrolling mechanic. The player must master the skill of fast reaction times, projectile aiming, and calculating a position to avoid enemy bullet patterns. The camera view is usually the top-down perspective, though it can also be a side-view perspective. Often the player pilots an aircraft or a spacecraft. the origins date back to 1962 when very early game developers created a space shooter titled spacewar! later, gamers would be introduced to two legendary arcade games titled space invaders (1978) and asteroids (1979). These two games brought the genre incredible popularity and began the golden age of shooter arcade games.
There are still many other subgenres especially for the shooter category because it has become difficult to classify. There are many possibilities and the evolution of shooter games means a greater mix of what is possible inside each game world. There is also a great deal of variance between player abilities, weapons, powerups, and boss fights. Some alternate subgenres have been suggested to further define the category.
Defining Subgenres
Bullet hell/Manic Shooter - Games where the screen is almost completely filled with enemy projectiles. Verticle scrolling is popular here.
Run and shoot - Games with horizontal scrolling where the game character moves on foot and can jump.
Multidirectional shooter - Games where the main feature is a free movement of 360 degrees.
