Nintendo has admitted that, yes, The Legend of Zelda: Skyward Sword has a game breaking bug. What is this bug and how can you avoid it? Warning: Spoilers.
The bug makes it impossible for players to complete the game's "Song of the Hero" quest. The save file becomes corrupted meaning that players either have to use an earlier save file or start again.
As website Zelda Informer (via website CVG) pointed out, Nintendo is stating that the bug arises if players follow this sequence of events.
1. At the beginning of the quest, go to Lanayru Desert to retrieve the song of the Thunder Dragon.
2. In the Lanayru Mine, speak with Golo the Goron.
3. Complete the Thunder Dragon's event, and receive his song.
4. Before heading to the forest or volcano regions, speak with Golo in the mine again.
5. At this point, the forest and volcano events will no longer occur, making it impossible to continue.
Okay, so that's how you get the glitch. Now, here's how Nintendo is telling players to avoid it:
• This issue WILL NOT OCCUR if the Fire and Water Dragon songs have already been collected before collecting the Thunder Dragon's song. Talking to Golo in the Lanayru Caves will also NOT trigger this issue.
• If the game has been saved after completing the sequence of events, it will no longer be possible to proceed through the game on that save file. The only options at that point are to either start the game over or to use an earlier save file to continue.
So if you, or someone you know, are experiencing this bug, this should hopefully clear that glitch right up.
Be sure to check out Kotaku's review of The Legend of Zelda: Skyward Sword.
Nintendo Addresses the Skyward Sword Game-Breaking Song of the Hero Glitch [Zelda Informer via CVG]