The colorful fish-themed graphics serve up enormous bosses and wild, detailed backgrounds. The eye-popping smart-bombs explosion displays impressive graphical prowess, but the action frequently slows down when things get too busy. On the sound side, CD-quality tunes nice pace the action, but the flat effects never take off. Completing every level of Gaiden will pose a formidable, enjoyable challenge to hardcore shooter fans. A weekend rental, however, will satisfy the less fanatical.