It's very much a game of it's time, it still looks nice and blowing enemies away feels cool, but the complete bullet-hell it is with just barely enough manoeuvrability to avoid the one-hit kills doesn't make for a good gaming experience these days. It is unashamedly a quarter-muncher (and shamelessly steals a page - nay, the whole damn library - from H.R. Giger's Alien), but it is easy to at least see why it was as iconic as it was.