This is a Underwater skyblock type map.
You start with seeds, saplings, mushrooms and sponge.
Command blocks give you underwater breathing.
Generated structures on.
Ores are layered downwards (all ores except coal).
There is a lava layers as well be careful.
Nether is accessible and is normal.

If underwater breathing doesn't start fly up and flip lever.


If you feel like it post some pictures in the comment section.