Countless times I lost the progress before due to a blackout, someone pulling the plug (by accident of course), running out of batteries, etc etc...
Seriously though, the game is really good despite the lack of music! Kept the tension up by constantly making me think: "Oh no, the power can go out any minute now, I have to hurry and get the other X stars, oh no, the screen just got darker, I'm going to lose all progress now, hurry, hurry, hurry!!!"