New Level Concept, MAD: Mutual Assured Destruction

I've been wanting to make a TC (Total Conversion) level for a while now, since I am more familiar with Unreal. I will probably be unable to contribute custom characters or guns, due to time restraints. I really want to focus on art AND gameplay in this new level, to show that I am competent in both modeling and level design. I am indeed an artist, though, and enjoy more of the lighting, modeling, texturing, and asset placement as opposed to scripting and white boxing levels (although I feel proficient in these, too). I am focusing my new level on a single-player style level for Unreal 3 and already have some simple AI systems that I've been working on to contribute. My major predicted obstacle is changing the core game mechanics: player ground speed, jump height, and ability to dodge. I have been researching mutators and have tried created a simple one to control these parameters, but to no avail. If all else fails, I will cater the level so that it works with both Unreal mechanics or any other.

Here is my concept:
-Based off the first Metal Gear Solid and ambiance of the Bourne Trilogy movies
-Player has to infiltrate a nuclear warhead/biological weaponry facility (not the most original, but I am planning on creating a fresh spin to the atmosphere and gameplay)
-There will probably be only a couple of guns -- stealth being the primary objective -- so a pistol with a silencer should suffice (again, this may have to change do to skill restrictions at the moment)

I am anticipating this level to take roughly 7 weeks to finish and will update any progress once I start production.