It looks like there are more than four racers on the track in some parts of the video... hopefully that means AI opponents.
And regarding finding the video, don't thank me, thank the fine folks at Nintendo Life. Part of the reason their site is so awesome is because they have a good relationship with many of the developers for WiiWare/DSiWare who often frequent the site to post news or just hang out and read the comments and feedback from users.
This one was discovered by another user on NL after a developer from Shinen' came over there and made a thread about the game's release date and website 
Until you've played it, every game is a system seller!
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mini-games on consoles, cinematic games on handhelds, what's next? GameBoy IMAX?
Official Member of the Pikmin Fan Club
