A video game developed by Treasure and published by SEGA in 1994 for the Genesis / Mega Drive. A different version of the game was also released on the Game Gear in the same year, and subsequently ported to the Master System exclusively in Brazil in 1995.

The game is framed as a stage play starring Headdy, a humanoid puppet with a floating head. Headdy is protecting his city from the terror of King Dark Demon, the self-proclaimed "world's greatest puppet", but is captured by one of Dark Demon's collector robots.
After being deemed unworthy and subsequently escaping from a garbage truck carrying other unworthy puppets, Headdy sets out to defeat Dark Demon and his forces by retrieving the wind-up keys of the Key Masters, large puppets who have been hypnotized into serving Dark Demon. However, he is pursued by Dark Demon's most loyal henchman, a purple (or brown) bear puppet named Maruyama (Trouble Bruin in the US and EU), who wishes to defeat Headdy initially to receive a reward from Dark Demon, but soon to take the play's starring role for himself.

Main characters:

Headdy - The protagonist of the game, star of the stage play Dynamite Headdy.
Headcase (JP: Mokkun) - One of Headdy's three friends, he appears throughout the game to allow Headdy to change his normal head into one of many powered-up heads.
Hangman (JP: Fukkun) - Another friend of Headdy's, who Headdy can grab with his head to reach higher platforms.
Beau (JP: Yakkun) - Headdy's last friend, who appesrs during boss fights to reveal their weakness.
Heather (JP: Fingy) - A mysterious female puppet. Similar to Headdy, she has a pair of floating hands and appears to be collecting the wind-up keys for her own purposes. In Stage 7, after throwing the wind-up keys inside of Yayoi / Gatekeeper, it is revealed that she has been collecting the keys to open the entrance to Dark Demon's castle.
Trouble Bruin (JP: Maruyama) - A bear puppet with the ability to change bodies, he is Headdy's rival and also the favored (albeit incompetent) henchman of King Dark Demon.
King Dark Demon - The game's main antagonist, the self-proclaimed "world's greatest puppet" who seeks to take over the puppet world. Upon his defeat, his true identity is revealed to be Smiley (JP: Smily), a smiley face-shaped badge meant to be awarded to the world's greatest puppet; however, he misunderstood his purpose and believed himself to be the world's greatest puppet instead.
Bino - An eccentric puppet who cameos throughout the game. Hitting him when he appears results in the player being awarded one of the game's Secret Bonus Points.