Well, you certainly got the overgrown style right. It's a cool environment to look at. I especially like the abundant vegetation growing on the walls. I have no issue with that as it doesn't get in my way. However, I can't say the same thing about the floors. There's simply too much clutter and unnecessary props that don't add anything meaningful to the overall experience. I got stuck in this prop model a few times whenever I encountered it through the level.
I understand that the ceiling has crumbled and all the tiles have scattered through the environment. It's logical, but it's not efficient. You can improve performance and navigation by removing more than half of the tiles. It also took me a while to figure out that I can use the gel on this runway. You should consider cleaning that area entirely.
Another thing I don't like are the moving panels. They play such an insignificant role in solving the puzzle that you might as well remove them; the elevator too (redesign so you don't need it).
Overall, it's a well thought out level. I like the fact that no bit of space is rendered completely irrelevant after you've gone through it; "reusability of mechanics" as you said. Though, I feel like it could use a complete redesign to make it simpler and compact. While you're at it, you should also consider improving the lighting by changing it to something like the image bellow. It will add depth to your environment and bring out the wall details.
P.S: That tree has become a cliche at this point.