The parkour is pretty repetitive, so try adding jumps like fences, ice, soul sand, heads, etc. It's got a pretty good difficulty and length, though.
The build could be improved quite a bit, in my opinion. Try shaping the dirt into actual islands, and maybe make the trees a bit more custom; change the colors, the blocks for the leaves, chisel them so they aren't perfect rectangles, etc.
The theme has been done before as well; in fact, I believe floating islands are the most commonly used theme on the server. Generally, unless you have a very good parkour/build, an unoriginal theme isn't likely to be accepted. Just a heads up for your next map. You can use Shinx's parkour list (seen below in my signature) to check what themes have been done!
Good luck!