Trigger Happy
Later games, such as R-Type (1988), took advantage of spare power to create an inventive impression of depth with “parallax” scrolling. Imagine the viewer inside the circular strip described above, only now it is not one but several concentric circular strips, revolving at decreasing speeds as they increase in distance from the viewer. In a train, the observer notes that trackside posts flash by in an instant, while distant scenery rolls past in a more leisurely fashion. In order to imitate this effect of moving perspective, the game screen background now acquires several different flat planes, so that objects in the foreground plane sweep by more quickly than objects in the middle- distance plane, which in turn pass more quickly than objects (mountain ranges, clouds and the like) near the horizon. The term “parallax” itself was, fittingly for a family of games that usually featured alien worlds, borrowed from astronomy.
It is important to emphasize again at this point that innovations such as wraparound and scrolling did not at once render earlier forms obsolete. The limitations of a fixed, bounded screen, for instance, are reimagined as positive gameplay virtues by the tense, claustrophobic design of Robotron (1982), in which the player’s post-apocalyptic hero must do battle in a
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