Boss Rush is one of the games that can be played in Minigame mode in Mario Party 9. This mode can be played by two, three, or four players and can be unlocked by purchasing it for 500 Party Points in the museum after all boss minigames have been unlocked. In this mode, players compete against each other in boss minigames to see who can receive the most points at the end of the game. If the player finishes first in a minigame, he or she receives five points; finishing second gives him or her three points; third gives the player two, and fourth gives the player one.
The player has the option to play against either the mid-bosses, the stage bosses, or all bosses. The bosses are fought in the same order as Solo Mode. Diddy's Banana Blast and DK's Banana Bonus are not fought in Boss Rush, due to the fact that despite being categorized as boss minigames, they are just bonus minigames, and Donkey Kong and Diddy Kong are not faced during them. The player with the most points at the end is the winner.
Oddly, if players choose to face all the bosses, they'll still end up getting only "10" party points in the end, even though there are "12" boss fights total.
 Minigames Played
Minigames marked with a * are mid-boss battles.
 In-Game Description
"Compete for Points in a series of six or twelve Boss Battles. The Player with the most points at the end is the champion."