I love the selection of instruments. They sound very realistic. The guitar is relaxing and enhances the melodies well. The melodies are what I would expect from this genre, but they're still enjoyable. The percussion instruments are interesting. They also sound realistic and add another layer of depth to the song. Although the vocals are good, I think you used too many effects on them and consequently, they don't fit with the rest of the song. In addition, I think you could EQ the vocals' high frequencies a little more. I like the firework and horse sounds! I keep hearing new details with every listen. I think the volume automation was a good idea, but maybe you could have raised the volume slightly less.
Congratulations on winning! I added this song to my favorites after my first listen.