Several Rhythm Heaven characters make appearances in Game & Wario, from the Chorus Kids being backup singers for Sal Out, to the Wrestler and Interviewer Girl appearing on the sidewalk in the Pirate minigame's opening. Additionally, the male character in Fever's Kung Fu Ball is Young Cricket from the WarioWare series. This opens up the possibility that the Rhythm Heaven series is set in the same universe as the Mario series. ...Which also means that the cast of Rhythm Heaven (along with the other Mario-related series such as Donkey Kong Country and WarioWare) was also affected by the events of Super Mario Galaxy and Super Paper Mario climaxes.
With the girl from Kung Fu Ball not only appearing in Move It, but being a prominent character rather than a cameo, and finally getting a canon name in Cicada, this is all but outright confirmed.
Left-Hand Remix in Megamix is, like the other end-of-game remixes in the franchise, a series of surreal scenes that play out one after another without any logical connection between them but is treated as if it's all perfectly natural. Such a thought process makes complete sense taking into account that it's All Just a Dream. Bearbara might be getting a fever...
What looks like a little slit right below Tibby's neck might appear to just be a spot, a fold, a bow-tie or some kind of weird shading might actually be something more. If what he grows up to be is anything like his mother, that is most likely a rhythm stage in development inside of him. This is made more apparent with his friend Colin, who has a door on his chest, just like the doors on the towers.
Look at the order of each stage in Megamix. The order of the four games every time (before the remixes) go from Tengoku (GBA)—>Heaven (DS)—>Fever (Wii)—>an original game in Megamix (3DS), and the pattern just keeps on repeating.
The executives in "Board Meeting" are boars, thus making them literalcapitalist pigs.
Why is the Challenge Train theme so long when it only takes a few seconds to show the next game and its conditions? Some of the later challenges (such as Frog Hop and Lockstep) require you to continuously press A/tap the stylus at a high speed for an extended period of time, so it's likely you'll need to wait a while to rest your hands. It was composed under the assumption that you would be waiting on that screen without doing anything.
The description for the minigame "Splashdown" expresses initial confusion about how there's an "I" in "synchronized swimming". In fact, there's 3 - one for each member of the team in the minigame!
A deliberate example with "Cheer Readers." The concept itself is silly enough ("academic cheerleading," basically), and then you remember that the pep squad is shouting encouragement in a library. (This humorously gets acknowledged in the Try Again screen.)
