The first time you buy a technique from the Dojo, Onigiri Sensei will "transform" in a similar fashion to that of Viewtiful Joe.

During the cutscene before the first battle against Waka, he says "Let's Rock, Baby!" This is a reference to Dante's signature phrase in Devil May Cry. Both games were created by Hideki Kamiya.
In the French verison of the game, Waka's speech translates by "Let's Rock, Baby! As a famous devil hunter will say some day!"
Waka's laser-flute's name is also named "Pillow Talk", the name of the ranking theme in Devil May Cry.

When Mrs. Orange makes the cherry cakes that she promises you, she does a similar move to the Raging Demon that Akuma does in Street Fighter.

There's an IGN watermark on the covers of both the Wii version and the official strategy guide.

Before the developers settled on the game's unique painted style, they intended the game to look realistic.