The space shooter genre became ubiquitous by the end of the decade, with games such as Galaxian and Space Invaders becoming commonplace in Japanese amusement centers.[29] As video games often depicted the killing of enemies and shooting of targets, the industry possessed a predominately male playerbase.[29] Toru Iwatani began work on a maze video game that was targeted primarily towards women, with simplistic gameplay and recognizable characters.[29][30] Alongside a small team of others, he created a game named Puck Man, where players controlled a character that had to eat dots in an enclosed maze while avoiding four ghosts that pursued them.[29] Iwatani based the gameplay off of eating and designed its characters with soft colors and simplistic facial features.[30] Puck Man was test-marketed in Japan on May 22, 1980[6][31] and given a wide-scale in July.[6] It was only a modest success; players were more accustom to the shooting gameplay of Galaxian as opposed to Puck Man's visually distinctive characters and gameplay style.[29] In North America, it was released as Pac-Man in December 1980.[32] Pac-Man's simplicity and visually-distinctive characters made it a fixture in popular culture, spawning a multi-million-selling media franchise.[33]