400 Hours: The Sixteen Day War

In 2013, we saw them.. They must have seen us a long time before, though...
7 years later, they entered an 18 hour polar orbit around our planet. At approximately 12:31 GMT, the first reports of attacks came from Eurasia...
At 7:35 EST, the first attacks against the United States were carried out by what we've come to call the "death-ships." By 17:00 UCT, the attacks were over, but reinforcements were deployed to the afflicted regions.
At 13:45 EST, the surviving representatives of the United Nations convened in the city of Saint Clark, Missouri. It was here that the International Confederation was established to combat this new threat to humanity. All states resistant to the agreement were considered "rouge and additional threats." Of course, nobody resisted.

By the end of the First day, it was estimated that 2.5 Billion people had been killed. By the middle of getting second the number had jumped to 3.2 Billion. On the dawn of the third day, the offensives began. The bastards deployed droids, drones and spider tanks. All attempts to quell the advance via conventional means were futile. At 5:55 UCT the Confederation gave complete authorization for the use of weapons of mass destruction. Russia, China and the U.S. immediately emptied their nuclear arsenals; Britain, France and the other nuclear powers followed suit soon after. We threw everything we had at them; Topols, Fengdongs, Le Terribles, Victorias, Churchills, Minutmen; you name it, we launched it, and though most were obliterated outright before they reached their targets, by God did it almost work. Apparently our adversaries had underestimated our capabilities, and over the course of a whole night we went from fighting tin cans to massive mechs and star cruisers.
It's the fifth day now; we 're throwing everything we've got at the clockwork assholes. Hopefully we can win...