The Adventure Tour in the DS version would probably make an impressive tool-assisted playthrough.
On the field, you'd periodically switch between playing as Mario and Sonic so as to use their different abilities, such as using pipes and springs, to progress.
Basically, you have to get crystals from the various missions sprinkled throughout the area in order to destroy the ice walls in your way. At first, only Mario and Sonic are with you but certain missions will get you more buddies. I'm fairly certain that to access the final bosses, you have to collect all of your friends. Thus, the trick is to figure out which missions to do to collect the crystals and which characters will get the missions completed the fastest, if not the best.
Also you have to collect items from chests to be able to participate in all of the missions.
There are actually two credit sequences in the Adventure Tour. One when you defeat Bowser and Eggman the first time and the other when you defeat them again after completing Bowser Junior and Metal Sonic's new challenges. The new challenges are fairly different and a bit more difficult (Speaking of difficulty, there is a difficulty setting but I don't know if it applies to the Adventure Tour as well as the normal single player mode) than the previous ones so it might be worth it to go for it and get the second credits.
Why, oh, why do I even <i>try</i> to understand my own species?