Hello,
Unfortunately I will be REJECTING your map submission for the following reasons:
Theme: The theme is not original as there is already a Heaven/Hell themed map (Heaven, HeavenVSHell).
Build: The build isn't bad, but typically maps should be one main build with parkour featured around it. The build you have made is a lot of floating jumps from island to island, so try to avoid having those kind of maps in the future. I appreciated the details on the Hell section with the bits of ribcage, but the Heaven section was very plain and not detailed.
Parkour: The parkour is the proper length and difficulty for a HARD map. However, the parkour is very repetitive, and almost every jump is just a block or a fence with a few ladders/soul sand blocks sprinkled in. Try to incorporate a wide variety of different blocks, such as heads, ice, flower pots, anvils, etc. to make your parkour fun to play. There were a few things that I found confusing, such as the presence of slime and ice blocks on the islands that didn't seem to add anything to the parkour or to the build, so I would get rid of those.
I hope to see more map submissions from you in the future, and have a great day!