This looks really nice. As in, really really really freakin' sweet. I haven't actually played SS13, but I've devoured the goonwiki and watched a couple gameplay videos (I also have just enough experience with BYOND to loathe it with a vengeance).
I have my doubts as to how well you're going to be able to pull off something with this kind of graphical/dimensional complexity and still have it run smoothly in large multiplayer games, but considering how laggy things are in the original... I wouldn't worry too much. And you actually seem somewhat competent at making stuff, which is disturbingly refreshing.
Here's a hearty congratulations on what you've accomplished so far, and some raucous cheering for your successes to come. We're all looking forward to that true Space Station Sensation.
Speaking of, how many simplifications are you sorta-planning on making? There are a vast number of things that are made inherently easier in a minimalistic, 2D interface... How do you intend to incorporate the ability for misleading other players, finding them out, plotting overly complicated acts of mayhem or violence (like oversaturating a room with oxygen and then setting up a remote signaler to cause a spark, or sabotaging the vent system to release an airborne contagion)? Also, unless you're planning on shifting things over to the planet (I have a very soft spot in my heart for spherical gravity centers in gaming), how do you intend to sort out the work miners have got cut out for them? An asteroid belt seems fairly reasonable, if somewhat resource intensive. It also allows for concealment, "swapping out" old asteroids for new to keep mining fresh, and installation of radio bouncers/jammers and evil syndicate death rays. What about monkeys? The blob? Changelings?
I'm certain there are going to be simplifications from the original, there almost have to be. And, in a few cases, I don't think much love will be lost. A first-person 3D environment already forces a stronger sense of atmosphere, so I'm curious as to what ideas you have for how this re-imagining should play out.