Mônica na Terra dos Monstros (Mônica in the Monster Land) follows the mold of past Master System games released by Tec Toy under the authorization of SEGA in Brazil, now for the Mega Drive (SEGA Genesis). It is a modification of Wonder Boy in Monster World, the last Wonder Boy game to be released in English. Mônica, however, is completely translated to Portuguese, like past games.
This version of the game has the same characteristics of past Mônica games: the characters from the original Wonder Boy are replaced by Turma da Mônica (Mônica's Gang) characters, and items are adapted to fit that series.
The levels remain the same, and very little other than graphical assets separate this game game play wise from the original mold, Wonder Boy in Monster World. The story follows Mônica and her friends as they fight enemies in order to rid the Monster World of evil.
Support characters work as travel companions, and comic book series' Cebolinha, Cascão and Magali serve as helpers to Monica in the many levels. Other than the usual 'suspects', other secondary and tertiary characters appear in the game's levels as store keepers and non playable characters. The angel, Anjinho, serves as a power up character that can be accessed once Mônica reaches the sky world.