Sadly, your map has been denied.
The concept of your map is very well done. You have a set theme in mind and it works to your advantage, however, some parts of your map feel less detailed than they could be. The main ending island, in particular, is very bare on the grass, and the bottom of the island does not look natural.
You could try bonemealing the grass to create flowers and wildlife. Also, it might be good to make some smaller island that, while not a part of the parkour, would look nice aesthetically. You can try to make the bottom of the island more realistic by creating spire shapes on the bottom.
Remember, you can always re-submit this map when you have made the needed edits, although you will need to create another forum post.
~ Billy