This stupid thing. That's 20 levels piled on top of each other. All I did was build the framework and resolve to fill in all those little buildings and spaces with rooms in 2D. ... Almost immediately it became clear that it was going to be slow going in 2D, so I went back to build the rooms in 3D.
That took months.
Then when I started rendering the new more detailed levels out and bringing them into 2D, I found that the resolution of the camera needed to be changed and now everything had to be resized before it could be brought into the original file. Bla bla bla. So much grunt work added to the process. Anyway, I got that done and started cleaning everything up again at which point I started to encounter render artifacts; missing linework, weirdly tapered lines that made whole rooms disappear, little bits of geometry poking through from the level above etc. I had to go back in to 3D and clean up a ton of geometry and rerender it. Gnashing my teeth and pulling my hair out the whole time.
A sane man would have realized how fucking pointless this is ages ago and binned the whole stupid thing. Honestly this was just supposed to be a bonus boss-monster fight with a mountain-sized bio-construct, with a little bit of running around inside the thing to get it to power down or something. I pictured a couple of key set-pieces inside and thought I'd mock them up real quick in 3D. Here I am almost exactly ONE YEAR later. If I quit now, it's all meaningless!
Oh how I cackled while writing that last sentence!
Here's a couple of the new levels to give you an idea of the detail of the undertaking:
All those large blank areas needed filling in don't you see-yeeeheeheeheeee gneeeeeeee