Some of the water blocks are opaque and others are translucent. Make it consistent. I think BWATER01 is a better flat for them. Most of the water blocks have sides, causing graphical errors when going from one Sector to the one next to it. Where the ground falls, the water has a rocky flat (when it should be a waterfall), and several areas don't have a colormap applied.
Overall, as the others said, it's too flat. It's possible to get lost (I went on the upper, middle path and wound up going in circles. It's hallway after hallway, simply jumping when it's needed or taking a Spring. There were no gimmicks and points of interest, and the Elemental Shield removes all the challenge (as the enemies underwater aren't a threat).
The scenery is really bland. It's random scenery Things thrown everywhere.
It's cramped, for the most part, but gets far too open near the end of the level. Especially considering that it's all empty space, it feels barren near the end.
There's multiple paths, but they branch together sorta quickly and none of them are interesting to warrant another playthrough in the first place. Other than the Elemental Shield, I don't remember seeing any bonuses.
3.8/10