- Divorced Installment: The first Wonder Boy game was later repurposed as the first game in the Adventure Island series, since Westone also had a licensing deal with Hudson Soft (in addition to the one they had with Sega, which kept the naming rights for the characters).
- God Does Not Own This World: Averted. All that Sega owned during the series' stay on their systems was the names of the games, while Westone owned everything else. This allowed them to port or license the games for other systems. Now that Westone Bit Entertainment is no more, it's Ryuichi Nishizawa, the creator of the series, who seems to have retained the rights, which he used to promote a spiritual successor to a legitimate sequel.
- Remade for the Export: Inverted. The original Master System version of Monster World II was never released in Japan, so the remake for the PC Engine (Dragon's Curse) ended up being the first version available there.
- Sequel First: Monster World II was eventually ported to the Game Gear a few months after its sequel Monster World III was released for the Mega Drive in Japan.
- Un-Canceled: Monster Boy and the Cursed Kingdom was relased in 2018, over twenty years after the original release of Monster World IV. While it has a different name and a new developer, the creator of the original series is involved, and has acknowledged the project as a legitimate sequel. Shortly after its announcement, two more projects popped up, this time with the original "Wonder Boy" title: a modern remake of Wonder Boy III: The Dragon's Trap and a reimagining of the original installment called Wonder Boy Returns.
Trivia / Wonder Boy