One Month Game Concept

So I hear there is a one month RPG creation contest out there.  I think just for the fun of it I'll throw my hat in the ring.

So let's break the game down into it's primary tasks.

1. Develop Core Mechanic / Game Concept
2. Character Creation
3. Equipment
4. Adversaries
5. World Building Tools

And I've got about 4 weeks to do this in.

I think I will attempt to make a rules light-heavy / medium-light post apocalyptic RPG based on an RPG that I had created about 20 years ago called 2049.

Game Concept of 2049

• Aliens observe humanity and decide to use humans as a warrior slave race to fight another alien species.  However, to be effective, humans need to be 1) neutered so they don't pose a threat and 2) genetically enhanced.
• Aliens threaten humanity with destruction.  Part of humanity secretly cut deal with aliens to survive and agree to serve humanity.  A secret head quarters is built on the dark side of the moon that is known to only a very select few.
• Aliens release "Genospawn" around the 2020 time frame, a plague/nano bot plague that is 80% fatal in adults, less so the younger you get.  The survivors have their DNA altered, often not beneficially.
• Nations of the world accuse each other of releasing the plague, as scientist  in league with the first alien race actually did release the plague without their national government knowing it.  Nuclear war ensues, but aliens destroy many of the missiles before they make impact.
• Most nations break apart.  Aliens begin setting up human run bases to observe and collect humans that mutated beneficially by Genospawn to be trained as super warriors.   

Players begin the game somewhere in the USA.  Here are the factions players can align themselves with.

• The Federation: The humans that work for their new alien overlords.  They have access to US military technology as well as advanced tech. Initially the Federation is a very small presence when the game begins, and eventually they become an increasing threat.
• The United States: What is left of the US federal government that survived the wars and Genospawn.  
• Survivalist: Due to the weakness of the federal government after the wars and the plagues, many municipalities no longer acknowledge the power of the federal government and have formed their own societies.
• Invaders: These are the remnants of a multinational invasion force made up of Chinese, Russian, and Latin American troops that are now essentially on their own in the former USA.
• EURO / UN Peace Keepers: Europe was left the most untouched by the wars out of any region in the world.  They have sent in various small expeditionary forces to try to get to the bottom of Genospawn.  

Players start out as a rag tag band of survivors in the USA.  Some adventuring ideas-

• Assist the USA faction on an attack on the Invaders
• Rescue a key person from the clutches of the Federation
• Avoid Federation patrols and make it a certain destination
• Find some devices in ruins that might help the EUROFORCE research into what happened.
• Attack rogue survivalist (or assist them) against other groups
• Explore areas outside of the USA to find out what happened.
• Destroy a Federation mining operation

Also the aliens have begun to terraform the planet, releasing all sorts of alien beast hybrids and changing the climate.  This new flora and fauna will be a continuing challenge to the players.