Connections

A Shroob, Stuffwell, and Luigi carrying Baby Luigi appear as stickers. Also, a cover version of the Gritzy Desert theme returns for the Mushroomy Kingdom stage. The boss theme was originally going to be in Super Smash Bros Brawl, but was removed in the final version. One of Luigi's poses in this game resembles his artwork for Mario & Luigi: Partners in Time.

When Mario and Luigi talk to Broque Madame, she tells them stories about the Shroob invasion that took place in the game. Several Shroobs are also seen at Bowser's castle, where they were kept frozen in a cryogenic chamber. If the player chooses to thaw them out, then an optional boss battle with them will commence. During the battle, several other Shroobs, including Elder Princess Shroob can be seen in the background. After the battle, Mario and Luigi tell Starlow about their previous battle with the Shroobs, and how they defeated them while they were babies. While the audience is still in the theater in Bowser's castle, a Shroob can also be found sitting in the audience on the bottom right. Also, there is a boot called the Shroob Boots. The theme that plays in Peach's Castle at the beginning is a remix of the present Peach's Castle theme of this game.

Poster shown.

Kylie Koopa appears in this game, along with a picture of a Shroob hanging on a wall in the house where she is found.

One of Luigi's poses in this game resembles that of his solo artwork from Mario & Luigi: Partners in Time.

When the wind blew away Baby Peach, Toadsworth the Younger asked the Baby Mario brothers to save her, saying: "You will save her, won't you? I assure you, she's NOT in another castle or anything." This is a reference to the repeated Toads' line: "Thank you, Mario! But our princess is in another castle!"

The cookies in Yoshi's Island reappear.

One of Shrooboid Brat's attacks involves having the audience giving him either fire flowers, mushrooms, or poison mushrooms. The poison mushrooms' appearance is exactly the same sprite of their appearance in the remake of Super Mario Bros.: The Lost Levels.

This game features the return of Baby Mario, Baby Luigi, Baby Bowser, and the Chomp Rock. Also the player can travel to Yoshi's Island, whose first area has the same music as this game's alternate title music. In addition, Kamek makes a reference to his attempted kidnapping of Baby Mario and Baby Luigi in Super Mario World 2: Yoshi's Island.

In the beginning of the game, the Cobalt Star shard is in a block similar to the regular Treasure Chest blocks in this game.