Shoot 'em up, or ShMUp, is a genre of videogames that is linked to both FPS and TPS games to a degree, but stems from older side-scrolling and top-down shooters, where accuracy and aiming were not considered as essential for completion. Good examples of ShMUp gameplay can be found in titles such as Contra and, in an extreme fashion, Serious Sam Double D. The main difference between a ShMUp and a TPS or FPS is the lack of a realistic game feel and the serious possibility of platforming.