OK so I just beat Eternal Sonata.  And I have to say, what the hell is going on in that ending?  What is Polka, does she represent some part of Frederik, and why'd she jump off the cliff become a kid and quickly get pulled right back up?  Who is the chick who sings Opera after Frederik dies?  And what in the world was with the catapiller and the snail story at the end, I was kind of hoping to get a little more insight into what the hell was going on in the game's story, but instead got some kind of wierd parrable. 

Anyone have any insight for me?

the ending was about death and how ppl view it. and about polka , she was a character in fredericks, whom he saw grow up and fall in love, also seeing how she did things. he couldnt let her die, also i think in his mind polka is fredericks version of his little sister who died of a disease, which is similar to the one polka has. so he decided to allow polka to keep on living so she could experience what his sister couldnt do in her little time she lived. and as for who is singing opera after frederick dies, that i dont know.

ok so that's why he didn't let her "die", but what about how apparently this has happened over and over again based on the tree with the many fortunes tied to it? That part confuses me as well.