While the port isn't necessarily bad, there are two glaring problems with the song. The first reason is because of the way you looped the port. The port plays notes after it looped, so you're adding huge amounts of unnecessary notes that only waste freespace in the rom. I suggest trimming the MIDI so it ends as soon as the loop happens, and re-porting the song from there.
The second thing was that the song could have been looped a lot better. Little to no effort was made to shrink the song. Something like:
1 
