More Brain Training/Brain Age 2
December 29, 2005
"Relax Mode" in More Brain Training (known as Brain Age 2 in North America) consists in a minigame called Virus Buster, that's actually a modified version of Dr. Mario.
Just Like in Dr. Mario, the player has to allign the falling pills (originally called "Megavitamins") to eliminate the same-colored viruses, however these are designed differently than in the original game. Gameplay-wise, the pills are here moved in the field by using the stylus, and rotated by tapping them; this creates two main differences in gameplay: first, the game sometimes drops two pills at the same time, since the player can choose which one to control with the stylus, and second, the player can now move pills pieces that are falling after others are destroyed under them, making it easier to make combos.
Super Paper Mario
April 09, 2007
In Chapter 7-2, called "Underwhere Road", the player's characters meet three guardian doors called Dorguys, that ask several questions to them, to see if they're worth of passing.
Dorguy the Second's questions have to do with memorizing the shapes, colors, and moving patterns of the geometrical figures that appear on his screen, referencing the various Nintendo DS games based on mind tasks, and specifically the Brain Training series. Also he waits for the player to answer all his questions before telling them if are right or wrong, and in the end he tells them their brain age or gives suggestion on how to train their brain, depending on how many right answers were given, further referencing the series.
Dr. Mario & Germ Buster
March 25, 2008
Dr. Mario & Germ Buster, known as Dr. Mario Online Rx in North America, is a Dr. Mario game available for the WiiWare that features a mode called "Germ Buster", based on the "Virus Buster" mode from More Brain Training. Note that in the japanese version there's no name difference from the game in More Brain Training (both being called Saikin Bokumetsu). In this mode the Megavitamins are controlled using the WiiMote, having the same gameplay features of the original game, but the virus design is retained from Dr. Mario.
Crossover Wiki note: The type of this link is quite arguable: it might be considered a type 3 or out-universe link with direction from Brain Training to Mario, meaning that the Mario series took some stylistic elements from the Brain Training series, in this case being the "Germ Buster Mode", thus considering Dr. Mario & Germ Buster only a Dr. Mario release, with the title basically meaning "Dr. Mario featuring Germ Buster mode".
Alternatively you can consider this a compilation of two games, thus considering "Germ Buster" a series on its own (that'd be a spin-off of the Brain Training series), and this would be an undirect type 3 link (meaning that the two games are only ideally linked from being together in a bounle), but there would also be a type 1 or in-universe link with direction from Mario to Germ Buster, because viruses from Dr.Mario make an appearance in this Germ Buster game.
We decided to consider the first case because Germ Buster hasn't received enough releases to be considered a game series on its own, and can rather be seen as a recurring special mode.
Copyrights for both series are held by Nintendo.