Game & Watch: Super Mario Bros. is primarily a side-scrolling platformer in which the player needs to make it to the far right of levels. The game also includes the Game & Watch game Ball, an action-puzzle game, however, the game is updated to make the character that appears in the game be Mario[3] (with Luigi also being playable through an easter egg)[4] - this makes it more like the final Game and Watch game released "Mario the Juggler", than the original ball, which features the "Mr Game and Watch" character. Although the "Mr Game and Watch" character is seen on the game select screen, he is not seen in the actual gameplay. The game also includes a clock function, which features 35 "little touches" (animations)[5] and easter eggs.[6]

Multiple easter eggs were also added throughout all three games, such as being able to give Mario infinite lives in Super Mario Bros. and The Lost Levels by holding the A button upon starting the game and being able to access and listen to the Mario Drawing Song (which included a language error)[7] by holding down the A button in the clock mode.[4]