The first game by Eugene Jarvis and one of the most iconic and popular arcade games of all time, Defender's relatively simple concept masks its high level of difficulty. Players control a ship trying to rescue humanoids on a planet's surface from capture by aliens, while avoiding their increasingly aggressive attacks. Development of the game began as Williams was chasing the success of Space Invaders and Asteroids, but ended up introducing numerous new concepts and ideas to arcade games that influenced an entire generation of games, including more complex control schemes, scrolling environments, multiple competing objectives and more challenging gameplay. Defender was followed by sequel Stargate the same year, which added various new enemies and mechanics.