Shoot ’em up games, or just STG, are not to be confused with FPS (First Person Shooter) games. No, the STG genre is the name we commonly use to describe games such as Spacewar! and Space Invaders. And they are ? true to their name ? completely focused on shooting stuff. For some reason aliens seem to be more popular to shoot at than other life forms (why we do not know), and as the player, your mission is to shoot them all whilst avoiding getting shot yourself. Simple huh?
There are a couple of different sub-genres to the shoot ?em up category. Fixed shooters are built up by levels that only require one fixed screen. Space Invaders is probably the best example of this, with aliens forming rows of varying difficulty moving further and further down the screen to get you.
Rail shooters are somewhat more flexible, but are still focused to a set ?rail? that the character must follow, often depicted from behind. Modern FPS games such as Call of Duty have been called rail shooters, though the flexibility of such games suggest they should be called something else.
All in all shoot ’em up is a dormant genre, as technology has pushed the boundaries of what can be done graphically, visually and movability wise. Some shoot ’em ups have made it to the cellphone and smartphone markets where they, do to their format, have become large successes, but on the computer or TV screens, their golden days have long past.