There's no demo, sadly, but you'll find all 91 levels of the original game here, including those that were added afterwards in subsequent updates.
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There have been so many moments in my life when I have found myself moved by a sound that, although Intdist.net intdist.net I may have been able to notate it, identify it's time signature or the key in which it was played, I would never be able to fully explain the sensation it gave me or my reaction to it.

However, it has a huge cost in terms of overhead.