That's excellent advice, actually; thank you! I'm working on updating the piece as we speak.

NEWEST VERSION:


first version:


Started this earlier today. I feel like I'm kind of wandering a bit aimlessly in regards to the anatomy and shading on the legs and pelvic region, though;

any C+C would be much appreciated!

I think in the future I should probably avoid making everything blue and reusing colors in so many spots, haha. In the process of making this I somehow forgot about the "value/hue" aspect of distinguishing between layers. 

http://imgur.com/tmrI6dv (direct link so you can see it on a dark background)
I'm working on an edit here and I took cues from both Anarkhya and Helm's edit, although somewhat subdued cues. The amount of colors has stayed the same although ptoing definitely proved the point that I could stand to shed a handful of them. I'm still working on separating them some more, though, so I don't think the process of reducing unnecessary colors will come until after then.

I'm happier with where it stands now but still working on it and tweaking it a lot. The things concerning me the most right now are:
  *Something feels off about the separated floor on the upper part, still, and I can't quite place it. Does it need more     separation on the bottom layer, or should I make it fade into black more?

  *I'm not sure how I feel about the tone, now; sometimes I get the impression that the colors are clashing in ways I don't want them to? But other times I don't.

  *It might be too dark still and I also don't know how I feel about the shadowing on the lower half. The pillars might be too light comparatively, as well.

Very distracting and annoying when in a game, you can't tell what's what, causing you to have to second-
guess where you can jump and where you can't. Bad design.

That was part of the original plan -- that you could jump on it -- but It's not set in stone. I've opted to remove it for the moment .

Imho, this is lacking in your mockup, and gives it an "all black and white" feeling.

Incidentally, the game started off as being black and white and more and more color has slowly been introduced. That hesitation is probably part of why I forgot to consider hue when thinking about the different layers and the result was something that was more of a flat range of blue shades. This is also partially why i'm keeping the colors less saturated.

I sincerely appreciate everyone's help here and I've gotten further with this and with my understanding of how I should tackle this kind of thing in the future than I would have otherwise! 

Candyman & Pypebros:

I opted to adjust the brightness and shading a little bit rather than add a detail like a railing; that adds more of a divide in depth than i want to have, as ideally the stairs should be only directly in front of the pillars behind it. I may still make the pillars darker but that's something I'm going to worry about when I've made some more progress. Similarly, I might edit the bottom part entirely to make some stronger shadows under the second floor and behind the two rows of pillars.

Ryumaru: Long time no see, haha. I've rebooted it a couple times since then and I've been working on getting my art abilities where I want them to be first. By mechanical, do you refer to tiling repetition, or do you mean the nature of the shapes?

In any case, I've got an update here.

I might be making the part above the "hole" something else entirely. Maybe something framed by columns with a sort of enclave in between them.