Chapter 1. 2D Twin-stick Shooter
The shoot 'em up genre of games is one of the earliest kinds of games. In shoot 'em ups, the player character is a single entity fighting a large number of enemies. They are typically played with a top-down perspective, which is perfect for 2D games. Shoot 'em up games also exist with many categories, based upon their design elements.
Elements of a shoot 'em up were first seen in the 1961 Spacewar! game. However, the concept wasn't popularized until 1978 with Space Invaders. The genre was quite popular throughout the 1980s and 1990s and went in many different directions, including bullet hell games, such as the titles of the Touhou Project. The genre has recently gone through a resurgence in recent years with games such as Bizarre Creations' Geometry Wars: Retro Evolved, which is more famously known as a twin-stick shooter.
