Three of them are promotional videos for different Nintendo competitions like World Championships 1990, Nintendo PowerFest 91, and Campus Challenge 92. I think the PowerFest 91 video is the most interesting because they are trying to get promotional partners with the video but the event they describe never happens. They describe it as a bigger World Championships with 100 cities, 10 semi-final cities, and a grand championship to be broadcast live on network TV. PowerFest 91 became known as Nintendo Campus Challenge 91 instead with a much smaller scale.
All six of the videos are great bits of gaming history and nostalgia. Some of the commercials, clothes, and haircuts make you cringe a little bit but they are very entertaining. It is also very obvious that the art of a promotional video has changed a lot in the last 20 years.
I've recorded all six tapes and uploaded them so everyone can enjoy these fantastic/awful videos.
Nintendo World Championships 1990 Recap
Nintendo Campus Challenge Sales Presentation
Nintendo PowerFest 91 Sales Presentation
Nintendo SCES (Summer Consumer Electronics Show) 1994
Ken Griffey Jr Baseball Promotional Video
"How We Do It" Promo (Basically why retailers should work with Nintendo)