The first game-breaking glitch in
Metroid Other M has
been discovered. Supposedly, if you backtrack a bit right after unlocking the Ice Beam and kill a few straggling sidehoppers, it will royally mess up your save file, making it impossible to progress and essentially forcing you to start over. I personally didn't experience this glitch but I tend to save my backtracking for the end-game item hunt.
The bad news is there is no easy patch fix for this problem--Nintendo's rather archaic online system for the Wii just doesn't allow that kind of game maintenance. The good news: Nintendo is still
offering a solution. If you save your corrupted (heh, Metroid Humor) file to an SD card and mail it to them, they'll fix it free of charge and cover the cost of shipping. Not the most elegant of fixes, but it shows Nintendo is dedicated to upholding their typically sterling customer service, rather than just letting their fans twist in the wind on this one.