game world, unlike most later games in the genre. The scrolling helped remove design limitations associated with the screen, and it also featured a minimap radar. Scramble, released by Konami in early 1981, had continuous scrolling in a single direction and was the first side-scrolling shooter with multiple distinct levels. In the early 1980s, Japanese arcade developers began moving away from space shooters towards character action games, whereas American arcade developers continued to focus on space shooters during the early 1980s, up until the end of the arcade golden age. According to Eugene Jarvis, American developers were greatly influenced by Japanese space shooters but took the genre in a different direction from the "more deterministic, scripted, pattern-type" gameplay of Japanese games, towards a more "programmer-centric design culture, emphasizing algorithmic generation of backgrounds and enemy dispatch" and "an emphasis on random-event generation, particle-effect explosions and physics" as seen in arcade games such as his own Defender and Robotron: 2084 (1982) as well as Atari's Asteroids (1979). Robotron: 2084 was an influential game in the multi-directional shooter subgenre. Some games experimented with pseudo-3D perspectives at the time. Nintendo's attempt at the genre, Radar Scope (1980), borrowed heavily from Space Invaders and Galaxian, but added a three-dimensional third-person perspective; the game was a commercial failure, however. Atari's Tempest (1981) was one of the earliest tube shooters and a more successful attempt to incorporate a 3D perspective into shooter games; Tempest went on to influence several later rail shooters. Sega's Zaxxon (1981) introduced isometric video game graphics to the genre. The term "shmup" is believed to have been coined in 1985 by the British Commodore 64 magazine Zzap!64. In the July 1985 issue, the term was used by the editor Chris Anderson and reviewer Julian Rignall. 1985 saw the release of Konami's Gradius, which gave the player greater control over the choice of weaponry, thus introducing another element of strategy. The game also introduced the need for the player to memorise levels in order to achieve any measure of success. Gradius, with its iconic protagonist, defined the side-scrolling shoot 'em up and spawned a series spanning several sequels. The following year saw the emergence of one of Sega's forefront series with its game Fantasy Zone. The game received acclaim for its surreal graphics and setting and the protagonist, Opa-Opa, was for a time considered Sega's mascot. The game borrowed Defender's device of allowing the