What is "sanvein"

is a top-down, multidirectional shooter developed by Success in 2000. Players can select different floors of various complexes to do battle with various enemies and bosses. Although the story is very vague, the game involves the attempt to escape from, and ultimately destroy, a giant space station called St. Schutz, a suggestively corrupted utopia; the player controls the titular Sanvein on such an attempt by battling with the station's defense mechanisms.