A Bonus Stage (also known as a Bonus Game) is a special mini-game found in the various Classic Modes (or 1P Game in the original) of the Super Smash Bros. series. They are used to interrupt the battle set-up, serving as a sort of "break" round. Completing the stage gives players bonus points that are added to their final score; additionally, completing some Bonus Stages under certain circumstances can unlock hidden elements of the game. Bonus Stages are always optional and do not have to be successfully completed to complete the mode.
In these games, the player is required to complete a certain task within a certain time limit and with only one life. Some bonus games feature custom arenas, designed specifically to test one's skill with a particular character and/or play to their strengths and weaknesses, while others use one universal stage.
Three bonus games are available in the 1P Game of Super Smash Bros., once every three battles: Break the Targets, Board the Platforms, and Race to the Finish. The main game can progress even if the player loses any of the bonus games.
In Brawl there is only one bonus stage: Target Smash!!, which appears twice after the fourth and tenth battles. The second time features a higher difficulty than the first, unless the first difficulty was already the highest. Snag the Trophies and Race to the Finish were both removed to make room for the second Target Smash! round. Unlike the previous games, the bonus stages are standardized for all fighters, only varying in difficulty.
Ultimate's Classic Mode features a stage named simply Bonus Game. This is a challenge in the style of Race to the Finish, but rather than having a time limit, the player must outrun a void of darkness that consumes the stage behind them. Glowing orbs in the stage can be collected to increase the player’s score. At the end of the stage there is a cannon that eventually leads to a portal, which ends the bonus game. Every character in Ultimate plays through this game before their final rounds. The only characters who play this Bonus Game earlier than their penultimate rounds are Mega Man and Ryu, who play it between the fourth and fifth battles, and Bayonetta, who plays it between the fifth and sixth battles. Bowser, Hero, and Sephiroth are the only characters who fight a unique boss or bosses before this game.