• EnglishWikipedia
In the Japanese version major bosses have short lines of dialogue before you fight them, which appears in a text box. In the western versions the only dialogue appears in the training sections of scene 2-1, and when Beau appears in the "Heathernapped" level.
There are some slight changes in the opening menu. In Japan the words "Press Start Button" appear on the title screen but in the west this is instead "Press Start". Additionally, in the controls configuration option the default move for the A button is described as "cancel", whereas in the west it reads "cancel head".
Some of the bosses had their designs changed when the game was transferred to the US and European versions. Aside from Trouble Bruin's color and facial change mentioned earlier, the castle-like humanoid robot "Mons Meg" in the US "Terminate Her Too" level was originally a large Alice-in-Wonderland-like doll named "Rebecca" in the Japanese version. In the "Headdy Wonderland" level, you fight a tall thin robot called the "Gatekeeper" in the US version, who turns into the "Nasty Gatekeeper". In the Japanese version, the boss is a tall geisha girl dressed in a kimono named "Yayoi", whose Nasty Gatekeeper counterpart is named "Izayoi". Mad Dog ("Bounty Boundy"), all of Trouble Bruin's (Maruyama's) various bodies (except the Floating Platform, A.K.A the Octopus Trap in Japan), and even a few enemies in scenes 3-1 and 9-1 have different color schemes in the US version, because they use the same palette line as Bruin and the colors were changed to look better within the level and compared to Bruin.
In the Japanese version's ending, the four Townsfolk from scene 1-1 are actually given individual names. They are "Maruco", "Mathai", "Luca", and "Johane". (Oddly enough, these names are references to the disciples Matthew, Mark, Luke and John.) Also, in the Japanese version, Maruyama's main body is identified as the "Kuma Body" (Bear Body), but went unmentioned in the US version.
The ending is quite different. In the US version, Smiley ("Smily") is overjoyed upon seeing Heather ("Fingy"), and Heather hugs Headdy. In the Japanese version, Smily is told that he is a badge belonging to the greatest puppet ever (up until that point, he is under delusions that he actually is the greatest puppet ever), and Smily proceeds to pin himself upon Headdy's face. Later on, where Headdy would see Heather off in the US version, he is busy trying to pull Smily off his face in the Japanese version. He manages to succeed in doing so, but Smily pins himself back on Headdy soon after.
There is a secret ending that can only be accessed by playing the basketball minigame four times and remembering or otherwise recording the "secret numbers" that are displayed. If this is accomplished, after the usual ending, Headdy will wander backstage and find a door that is locked with a digital keypad. By entering the secret number you were given, Headdy opens the door only to find himself in the office of the theatre's owner. The owner, incensed that a puppet escaped, orders his thugs to attack Headdy by throwing dollar bills at him (which are extremely damaging; three hits from the money can kill you). The battle is made easier by the fact that Headdy has unlimited lives at this point, so the player can take as many tries as needed. After the owner's thugs are defeated, he starts throwing homing bills at Headdy. Eventually, the owner of the theatre is defeated, and Headdy runs outside, flings his head upwards, and pulls down a "The End" sign. In the Japanese version of the game, the theatre owner and his thugs are replaced by the then-president of Sega of Japan (Hayao Nakayama) and two security agents, who act no differently from the owner and thugs. The American secret ending can be interpreted as Headdy triumphing over the greedy theatre owner (who most likely caused Smiley to become evil as a way of spicing up the play) and freeing his fellow puppets, while the Japanese secret ending is just a surreal jab at the then-president of Sega of Japan.
In the practice areas in Scene 2-1 in the Japanese version, the player is presented with a "yes/no" text box asking if he or she is sure that Headdy would practice utilizing his friends' abilities. If "no" is chosen, Headdy returns to the main section of Scene 2-1 after a few more words with the friend. Furthermore, if Headdy fails any of the practice areas in the Japanese version, his friend in that area would talk to him before he returns to the main field.