Some of the Boxing Ring Stage titles contain references and easter eggs.

Luigi's, "The Eternal Understudy", is a reference to his unlock screen in the original Super Smash Bros..

Fox's title in the European version "Never Gives Up! Trusts His Instincts!" is a reference to a line in Starfox 64 said by Peppy in the Asteroid Belt level (and later on said by Fox's father).

Kirby's European title "Gritty in Pink" is a reference to the movie "Pretty in Pink".

Sonic's European title "Speed is his Game" is a reference to one his popular quotes "Sonic's the Name, Speed's My Game!".

Pikachu and Jigglypuff's European titles are actually just their Pokedex names.

Mewtwo's title "The Legend Reawakens" is a reference to the title of the Pokemon anime movie "Genesect & The Legend Reawakens".

Lucas' European title "The Tazmilian Devil" is reference to the Tasmanian Devil.

Roy's title "The Young Lion" references the title given to him at the end of Fire Emblem: The Binding Blade.