Plot: Your ship lands in a valley on Na Pali. You head off to do your mission while the rest of the crew wait. In a Skaarj mine facility a powerful radiation based energy core is being constructed. Your goal is to find this, then decide what the best course of action is from there. You have a feeling this isn't going to be easy, but you try to stay optimistic.

Notes: I am hoping to create a map layout with lots of connected areas and some cool secrets, like you might find in Doom. There are some other ideas I want to try to implement in my map as well. This contest is a chance to experiment.
Update- this map seems to be going in a slightly different direction to where it was planned. Well, I'm happy to take it there.
My free time is probably going to be limited, but I'll spend every single second of it mapping playing Portal 2.

Pictures:

Couldn't help but dump a picture here of the start of my map. I'm looking to create a style similar to Nyleve/Neve/etc. for a while. It uses Tessellated cube terrain which I recently learnt how to do! It hasn't fallen through a giant BSP error yet either!

I like where this is heading.

Great start!

Ha, I had a lot of free time today and got a fair bit done. Although all the work so far is only just leading to the main bit of the level, the mine itself. That is where the action is going to be.

There will be a second picture tomorrow (unless everyone is against the idea of spoiling the map with preview images ).

I didn't get much time at all to map today. Been busy moving stuff... And playing Portal 2. What a distraction!
However here is an image as promised:

This bit of the mine has seen better days.

A question: What are good techniques to make buildings looked ruined, for the exterior and the interior? I am knocking things over and putting plants and webs all over the place, but are there some nice techniques to add further looks of disuse and desolation?

Cracks, visible and/or broken infrastructure such as wires and pipes, leaking liquids (there's a drip generator you can use) or gas, non-functional lights, etc.

Looking good so far.

I don't know what everyone else does to make stuff look ruined, but here's what I do.
(I put the images in as URLs so that I don't clog up your thread)

http://img51.imageshack.us/img51/6505/example1p.jpg

Go in the 2D shape editor and make a shape like the one in the link above. Then do Extrude to Point (and make sure the point thingy is in the center of the shape).

Once you've done that, line up your 2d shape with a wall or a column, like so:

http://img594.imageshack.us/img594/6209/example2ni.jpg

Then subtract, and viola! You got a crack in the wall. The example shape I made doesn't look very good, though, so try to make your shapes not so square like; make them kind of uneven. I think this is the method that Epic themselves used when making scars and cracks in maps like Velora or Ruins. I've been using it for a while, and sometimes it turns out okay, other times not so much, but it's probably because I'm terrible at making 2D shapes.

Edit: You might actually want to put the point at the bottom of the shape. I'll have to experiment a bit to see what I get.

Edit 2: I just noticed I'm a Skaarj Assassin.

For the perfect example of "ruined": See Chico

that's looking really good! holy crap are you guys ever fast!

I really like the 2nd shot alot LS222. Has a high quality stock Unreal feel to it. Nice touch with the plants.

Thanks for all the nice comments.

Been doing a lot of hard work today (read 'hard work' as 'Portal 2') so I haven't gone on miles but I did get some stuff done. I've mostly finished off the first section of the map, the end of the section being defined by a change in music tracks. However that part was quite easy to design gameplay wise because it is mostly tentacles.
Now I have to design real combat and already my terrible knowledge of paths has left some ambushing Skaarj sitting at home taking a nap.

Doing some mapping now. Look at this door I just built!


With glass panels.

Also listening to some music right now that actually fits the theme of my level.

More stuff! This is some more of the ruined mine area.


Hard to see but there are drops (in front of the broken door) leaking from a pipe. Also just out of sight are broken screens, webs, broken fans, smashed open floors and such.
Thoughts?

Also In the Air isn't really a bad title so I think I'll keep it. Unless you can think of something better!!

Looking good. You might want to add some gashes in the wall, and maybe a couple of loose bricks or something to give it a more ruined feeling to it.