Links: TVTropes, Wikipedia, IMDB (7.3).
Imagine F-Zero, Rock n' Roll Racing, Extreme-G, Speed Racer, Akira, and Sailor Moon thrown into a blender, violently puréed into a chunky paste, and then gulped down with a bottle of Tapatío and a raw egg. That's pretty much the best description I can think of for this film. The foreground plot is pretty generic; the background plots straddle the line between nonsensically elaborate and totally random; and, well, you're not really going to get much in-depth character exploration either. BUT IT'S SO SHINY! AND IT HAS GIANT COSMIC HORROR MONSTER BATTLES AND DRAG-RACING POP IDOLS WITH MAGICAL PRINCESS POWERS AND CYBORG SPACE NAZIS ON SUPERSONIC ROLLERSKATES! Score: eh, 3 stars out of 4 (the middle drags, between the races they forget they're not in a serious movie).
P.S.: A friend aptly said of this film, "I'm surprised this movie didn't travel back in time so it could retroactively be in Heavy Metal".