Raiden reached arcades in September 1990 and became the breakout success of its developer, Seibu Kaihatsu, after years of lower-profile releases. Distribution was split by territory: Tecmo handled Japan while Fabtek brought the game to North American operators. Players pilot the Fighting Thunder fighter craft against an alien invasion, working through eight densely populated stages of ground turrets, tanks, warships and airborne squadrons. Its weapon system became the template countless later shooters borrowed from – a red Vulcan cannon that widens into a spread as it powers up, a blue laser that concentrates damage into a narrow beam, and two secondary missile types, one dumb-fire for raw damage and one homing for crowded screens. A second player can drop in at any moment for simultaneous co-operative play, doubling the firepower and the chaos. The relentless volume of enemy fire, punishing but readable, pointed directly toward the bullet-hell subgenre that would dominate Japanese arcades later in the decade, and the game spawned a series still running today.