I remember Patrick saying something about a secret ending... I wonder whether there might be an extra level (bringing the total up to the much more likely-seeming 110) which needs them to unlock it......... I think I've been fairly diligent in trying all four arrow keys on every level that I've visited, but I guess I might have missed some, or perhaps you have to do something else to get at it? I haven't noticed hidden signs in any levels...
I'm not expecting anyone to say what it is, but it would be nice to know how "warm" I am. Is there a different reason for those spare stars (which seem to have accumulated throughout the various sections)? Are they just to give a bit of leeway to players who get stuck on a level? Come to think of it, I could probably have completed the game without doing any of the levels in the Void...