- A retro mini-adventure for Game Boy -A retro mini-adventure set in the Jett Rider universe. Rescue trapped Gravonites, explore dangerous mines, and become a true handheld hero in this classic Game Boy-style experience. Peace has finally returned to Gravos. Fusion Bot is gone, the temples are silent, and Jett Rider is enjoying a rare moment of rest. Until a cave-in at the gravitonium mines traps villagers underground. With his break cut short and his sandwich abandoned, Jett jumps back into