BoxBoy! + BoxGirl! is a Puzzle-Platform video game created by HAL Laboratory and published by Nintendo for Nintendo Switch. The game supports both Single-player and Multiplayer modes, and it serves as the fourth main title in the series of BoxBoy video games, also the first to be released for Nintendo for Switch. It serves as the follow-up to Bye Bye BoxBoy video game released in the year 2017. The game introduces the two-player multiplayer mode for the first time in the history of the series. However, similar to its previous titles, the premise of the game is puzzle-platform elements. The core gameplay mechanics focuses on regenerating a chain of boxes to take on challenging obstacles and also to reach the end of each level to become the master. There are several levels, and in each level, the player can generate limited boxes that can be created at a time. Moreover, the boxes can be used for a set of functions, pressing switches, and blocking hazards. In the single-player campaign, the player controls Qbby, and he aims to create strings of boxes which can be placed down, retracted, or held out by Qbby.