Sooo, my review (My English is really bad, sorry for that :x):
Positive point :
-Your build looks really good, I see you put a lot of time to build this parkour, and a lot of part look really nice like the Rainbow cloud c:
-The theme is pretty decent, I don't know if this theme was used before but your build it's pretty clear.
-They are some good idea in some jumps (like the "invisible" diamond jump part)
Negative point :
-Your parkour is REALLY confusing, I hit invisible block a lot of time and that was really frustrating (Especially in the Rainbow cloud part). Please, put some sign on some invisible block and some arrow.
-The start is in a badly place, I think you need to put the start at the space where you spawn when you teleport in your plot.
-The parkour is not really varied, 60% of your jump is standard jump and 30% is ladder jump. Put more fence/ice/soul sand/invisible jump ...
-At first, I don't really understand the invisible part, so please, put something in the first invisible block to help people
-This part (Go see the screenshots) is the most confusing part :
If someone jump and fail this jump, the person is lost because they don't see the invisible block (And not the hitbox of the invisible block) and they thinks it's totally invisible wall.
-"90" jumps is too long for a Hard parkour, it's more an Expert parkour than a Hard.
I hope I help you c: