Bing Bong Bong Bing Bong DUNNANANANANA!
I think the opening bit goes on a bit too long. The song's not bad, but that part could rather easily turn away the sort of people who'd enjoy this the most. The more redeeming parts of the song where the melody starts standing on it's own tend to not really come into play until after the 2:30 mark, which is a lot of time for someone to have to wait for a song to finally hit true stride.
Aside from that, not a huge fan of some of the instrument choices, but they kinda come with the genre so I can't dock you too much on that one. You vary the focal sound on a regular basis as the song goes through, which is totally a good thing and given the length and amount of variance this goes through pretty impressive.
I think of the lot the piano's melody is probably the highlight of the song for me, but in the end it's pretty well-balanced, though it takes a bit too long to get going and could use some minor tweaks here and there.