Heya Mine!
Just going to be giving my opinion here on your map; keep in mind that I am not a map judge.
In regards to the THEME, there is no distinct one and I would advise you to rethink the theme entirely. Try and create something which is distinct and unique, make it stand out!
You can find a full list of already accepted maps here:
Maps list
In regards to the BUILD, it is mainly floating and does not have a "main build" of sorts. It's best to create a build and then incorporate your parkour within and surrounding that. Make sure to add a lot of detail as well to make it look pretty!
Your PARKOUR is mainly floating, which is no longer accepted on ManaCube. Again, try to create a build and incorporate your parkour within this, easy fix! The length fits that of a hard map, but I believe the difficulty is inconsistent throughout, so try to balance this out.
The jumps are also very repetitive, same with the blocks used for the jumps; therefore, I recommend the use of blocks such as piston heads, water, player heads and trapdoors.
I hope you can take my opinion into consideration <3
Cheers.