type, a more advanced enemy type replaces it. Destroying flashing-red "Zolback" radars found on the ground will cause the game to switch back to easier enemies. Certain points in the game have a fight against the Andor Genesis mothership, which launch an endless stream of projectiles and explosive black spheres known as "Zakatos". The player can either destroy all four blaster receptacles or the core in the center to defeat it. Some parts of the game have hidden towers ("Sol Citadels"), which can be found by bombing specific parts of an area. The Solvalou's bomb reticle flashes red when over one. Yellow "Special Flags" from Namco's own Rally-X are found in a semi-random section of the area. Collecting one gives an extra life. Development Xevious was designed by Masanobu Endō, who joined Namco in April 1981 as a planner. He and a small team were assigned by Namco's marketing department to create a two-button scrolling shooter that could rival the success of Konami's arcade game Scramble (1981). Early versions of the game were named Cheyenne and took place during the Vietnam War, with the player controlling a helicopter to shoot down enemies. (The original name may refer to the Vietnam-era Lockheed AH-56 Cheyenne advanced attack helicopter project.) After the development team was reshuffled and the project planner quit altogether, Endō became the head designer for the game. He learned programming on the job during production. Endō wanted the game to have a consistent, detailed world with a story that didn't feel like a "tacked-on extra", instead being an integral part of the game. The goal of the project was for the game to be inviting for newer players, and to become gradually more difficult as they became better at the game. Influenced by ray-tracing, Endō wanted the game's sprites to be high-quality and detailed, while also making sure they fit the limitations of the arcade board it ran on. The team used a method that involved giving each sprite different shades of gray, allowing sprites to display additional colors. Many of the sprites were designed by Endō himself, although some were done by Hiroshi "Mr. Dotman" Ono, including the player and the background designs. Many of the game's characters and structures were designed and refined by Shigeki Toyama, who previously worked on many of Namco's robotics for their amusement centers in the early 1980s. The player's ship, the Solvalou, is