While this map is fine, I think it lacks a real focus. The stage ends up just feeling empty and directionless.
There are a lot of areas that lead to a monitor that doesn't end up adding anything to the level design. The monitors feel
like they're just there to be there.
You could've used the slime as a gimmick throughout the stage, but you only used it at the end.
Visually, there are many textures that feel mismatched with the "cloudy and gloomy" description you listed.
(Specifically the pink walls and the grey triangle checkerboards.)
If you could tighten up these problems for this stage, or even your next stage, it'd be great. I would definitely like to see more levels from you!