Gekioh is an enhanced port of Shienryu. This release adds the following game modes: - Pocket Mode: imitates PocketStation graphics, with deliberately primitive visuals consisting of heart-shaped enemies and blocky ships. - Comical Mode: music and sound effects are replaced by laughter and applause (when the player reaches a high score). - Stingy Mode: the player has only one life and no continues; only two levels are playable. - No Mercy Mode: a harder difficulty level. - Slow Mode: darker graphics and sound effects reminiscent of horror themes (e.g. enemy and player-controlled ships scream when destroyed). All sprites on screen move slower, but the amount of bullets fired by enemies is increased. - Ancient Mode: the screen has a yellow tinge and displays "cracks"; music is changed to reflect a "retro" setting.

Natsume's vertical scrolling shooter Gekioh: Shooting King offers nine arcade-style modes of nonstop action in a futuristic setting featuring giant mechs, laser-firing, bomb-dropping airships. Environments are filled with power-ups, explosions, and destructive mayhem. Players wield an arsenal consisting of a devastating Vulcan cannon, electrically charged lightning attacks, and missiles capable of decimating ground tanks and flying squadrons. Power-ups include increases in speed, power, shields, bombs, and point bonuses, with the primary weapon changing depending on the last red (cannon), blue (lightning), or yellow (missile) disk picked up.

Gekioh: Shooting King features three main levels of difficulty: Geki Mode (normal fire rate), Easy Mode (enemies have half the rate of normal fire and collisions aren't always fatal), and Hard Mode (double firing rate and stacked odds). Six bonus modes are available from the beginning of the game (no unlocking required) and offer diversity in gameplay. Modes include Comical (damage accompanied by a laugh track), Stingy (one aircraft and one special weapon), No Mercy (unerring enemy fire), Slow (slow enemy fire but rate-multiplied), Ancient (bleached out color to eliminate power-up recognition), and Pocket (block-shaped symbols in basic form).