Build: Personally, I don't think the build is very good. For starters, it doesn't portray your theme accurately. There's so much you can do with the theme and all you did was use nether-themed blocks for the parkour and add 2 oddly placed nether-themed boxes. You need to be a little more creative. Furthermore, the build was also not attractive due to the poor parkour integration and lack of focus. The majority of the build is just the parkour and that's unacceptable. We want you to make a central build that portrays your theme accurately and integrate your parkour into it. You must do these things in order to have a map that is in an acceptable condition.
Parkour: The map is long enough for the medium difficulty but I found it to be rather easy, I'd recommend you buff it a bit. But, there's a bigger issue: repetitiveness. There were too many instances of the same block/jump being used consecutively, proving to be a very unenjoyable parkour experience. You need to make your parkour be more varied whether it be by using different jumps (especially) or blocks.
I hope you take these criticisms into consideration when submitting maps in the future, good luck!