Casual games are a sub-genre, they can exhibit any gameplay. They are typically identified by simple rules and low requirements for timing and skills. Usually, casual games impose low production and distribution costs, which is why developers widely produce them. Casual games can perform at any platform; they do not require any individual peripherals. Usually, there's no need to save to continue later, mechanics include a one-button mouse or cellphone keypad, but the gameplay is still puzzling and elegant. They also have simple gameplay and allow to take breaks between rounds without losing interest in it. The first well-known game of the genre is an arcade Pac-Man released in 1980. However, actions, graphics, and sounds are often quite limited but can display additional features in multiplayer modes. Simplicity along with elegance aren't the only traits making the genre popular; these games are also quite cheap.