The game should not be confused with Wonder Boy III: Monster Lair, which despite being made by the same people and carrying a similar title, focuses more on being a side-scrolling shoot-'em-up with platform segments.
Gameplay is similar to Monster Land, however the hero, Wonder Boy, finds himself cursed early on in the game and spends his time defeating other dragons to return to his human form. The game was highly received for its gameplay and music, and is often even said to be one of the greatest Master System games of all time. It was given the 1989 Game of the Year award by Electronic Gaming Monthly.
An arguably better version (minus the Wonder Boy branding) exists in the form of Dragon's Curse, released for the TurboGrafX-16 in the years that followed. Confusingly this version of the game is known as Adventure Island in Japan, though bears little resemblance to the Adventure Island franchise, itself branding off from the original Wonder Boy game.
The Dragon's Trap was also brought to the Sega Game Gear in 1992. International releases of this port dropped the "III," calling it merely Wonder Boy: The Dragon's Trap (a prototype ROM with the original name circulates around the Internet).
Both the TurboGrafX-16's Dragon's Curse and Wonder Boy III: The Dragon's Trap have been released on the Wii's Virtual Console service, despite being roughly the same game. A similar situation occurred with the sequel, Wonder Boy in Monster World.