Thanks heaps for the responses guys, has already given me some things to think about and confidence in some of my initial assumptions, even gave me some "adventure" ideas as well :D
That sounds a bit like the setting of Vorkosigan Saga. What if after that you have a more authoritarian and warlike culture in what used to be the major nations? Of course that is not a precise comparison to Barrayar which was authoritarian and warlike beforehand and survived by becoming more modern.
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"The navy could probably win a war without coffee but would prefer not to try"-Samuel Eliot Morrison
That sounds a bit like the setting of Vorkosigan Saga. What if after that you have a more authoritarian and warlike culture in what used to be the major nations? Of course that is not a precise comparison to Barrayar which was authoritarian and warlike beforehand and survived by becoming more modern.
Its amazing how close you are to the mark with this one, for those that might be interested the story of the game brokes down like this:
Spoiler:
There are two other main alien races, The Ur'Quan (stolen from an old game, cookies for those who remember this one)
Squid like creatures that hold a form of religious belief / system of morals whereby life in the universe is more sacred then free will or sentience, to adhere to this when they encounter a sentient species that appears to be headed on a path that will greatly damage life on a planet they will send an automated occupation fleet that will invade, cull and finally occupy said planet to ensure its sentient species do not become a threat to it again. I think i set these guys at TL9/10 with some super science added for space travel.
The Grey (stolen from...everywhere)
Tall Slender grey aliens that possess telepathic abilities, extraordinary intelligence, very long lived but with a very small birth rate, and by human standards would be called emotionless or outright callous. They care little for life and are typically a cowardly race. Note - they do not refer to themselves as "The Grey", they communicate mostly through telepathy and telepathic imprinting on objects, and also they have an old form (to them) of hieroglyphics (yeah its soft science all the way lol), I tried to impress this a little in game by having the communication with them be very basic and even when a human psychic communicates with them telepathically the human just gets flashes of their own memory as responses ie if the Grey wants to so "no" they may get a flashback from when they were a child being to they could not have a cookie before dinner etc. These guys i started at TL10/11 again with some SS for space travel.
The story
A long time ago in a galaxy far far away....The Grey empire was discovered by the Ur'Quan hive mind, naturally the Ur'Quan quickly set to declaring all-out war on the Grey. While far superior in technology the Grey were vastly outnumbered and had not fought a war in over three centuries (and thus having to build all their troops from scratch), combined with their natural cowardice this puts them into a losing battle.
During one such battle a Grey mother-ship (yeah I know i reeeaalll original lol) is attacked and attempts to escape is attackers using *insert FTL tech* (in the original story because it was never going to be off earth i completely skipped explaining how the aliens whizzed about the galaxy lol), during transit damaged caused by the battle causes a miss-jump and the ship crashes into a moon that orbits a little blue planet. Enter Earth 1942, pilots report seeing "glowing orbs" in the sky that defy gravity and move in impossible ways (these were the escape pods from the crashed mother-ship, small vessels in their own right but not FTL capable), the governments that are aware of the crash scramble to cover up the existence of aliens to avoid panic and to get to the moon to recover what they can (the space race begins), so on an so forth for the next 60-70 years of shady government wars, black operations and X-Files(again originality my strong suit).
Meanwhile the stranded Grey first begin by trying to establish a distress call to their brethren for rescue. With most of their equipment damaged they jury rig some of the archaic human technology in order to transmit a radio signal. Knowing that it will be at least fifty years before the signal will reach a listening station they begin to study the inhabitants of the planet. As they learn more about the species they become increasingly intrigued. They come to the following conclusions, the human race is among other things violent, intelligent, hardy, easily controlled (by their standards), loyal, brave and extremely cunning in the art of war. All the traits one would want in a soldier. They continue to test the species with various experiments including purposefully leaving technology for the humans to find that is close to their own TL but slightly more advanced to see if they can reverse engineer and use it themselves (with the added bonus of shortening the wait for the Grey if the TL advances enough).
Contact is re-established with the Grey Empire in 1994, having studied the behavioural and societal aspects of the species, the Earth bound Grey have a plan to bring them into the war as a weapon. All they need is one Ur'Quan Dominator class ship (essentially the ship from Independence Day...again Mr.Original lol) to run a false flag operation. The plan is to attack Earth under the guise of the Ur'Quan using their own principles and equipment, de-stabilising the current world order by purposefully leaving one of the major nations in a superior position (in this case Russia, due to my fictional worlds stockpiles left over from the cold war - again alien based, in this world Russia and America had thought each other had either acquired too much alien tech or had been infiltrated by the aliens) which would survive the coming EMP strike in better shape and then receive a slightly less severe second strike by Ur’Quan shock troops, finally as the humans are at their greatest point of peril the Grey will “Show up” and offer their assistance explaining they too battle this enemy and want to save another race from being enslaved and destroyed. After the war is resolved the Grey will give assistance in rebuilding Earth, offering new technologies and scientific insights.
The plan will then be to reshape the human race into a weapon for use against the Ur’Quan, by manipulating genetics very slightly over hundreds of years (part of the plan is to introduce the concept of growing people for mass production) and changing the way humans think and reforming their culture to make them the perfect soldiers for the Grey and all the while have them think of the Grey as a close friend and ally. Meanwhile they will attempt to blind the Ur'Quan to the human threat until it is too late for them to counter the tactic. Once the war is concluded they will again manipulate the human race, slowing their reproduction, easing the aggressive tendencies and ensuring loyalty remains so that should a similar threat arise in future the soldier race can be roused once again.
*As the back story is a bit off topic i have started a new thread for it, see below