You are filled with determination. (R/GD/TT)
This is something that just bugs me so much. These games are crossovers, but are not exactly treated as such. For those that don't know...
- In Captain Rainbow, Birdo is one of the characters that the protagonist helps out
- In Densetsu no Stafy, Wario helps out Sta(r)fy throughout all of World 8
- In both SSX on Tour and NBA Street V3, Mario, Luigi, and Peach are playable characters in the GameCube versions of the games
- Probably some others I missed, feel free to mention them.