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Uses two-dimensional "sprites", 2D images created and used on a flat plane, as opposed to the three-dimensional models or environments found in 3D games.

PICO-8 is a fantasy console powered by Lua. Games are distributed as cartridges which double as PNG  images. 

Shoot 'Em Up or shmup games are a subset of shooter games where the player continually moves forward while waves of enemies enter the screen. Both shooting and dodging are critical to advancing. See also Bullet Hell.

Games which have short playtimes and can usually be completed in one sitting.