If I might break into this discussion, I would like to make a few suggestions, particularly to the Mumbai incident (and subsequently, altugi's idea about Phalanx v Alien "Phalanx"). It has been commented that if the aliens were capable of such an attack then an uppity upstart organization like Phalanx wouldn't have a hope of defeating them. This is quite true, if the aliens were capable of performing such an attack on a regular basis. The key to winning almost any war, especially a war of invasion, is to destroy the morale of the opponent.
In short, what if the Mumbai incident was the alien equivalent of going "Hiroshima & Nagasaki†on humanity? That is, they staged a dramatic attack that they are incapable of following up in a similar manner. They had absolutely no intention of occupying the city, but rather they wanted to make humans believe that they are an unstoppable force. Imagine that after weeks of heavy fighting, as humans take back the city block by block, they continuously see mangled human corpses, destroyed buildings, flaming wrecks, but slowly they begin to notice something is missing. There isn't a single dead alien, there isn't a single bolt from one of their machines, to prove that they were actually there. What if it appeared that they weren't driven out of the city but choose to withdraw (as indicated by lack of corpses).
Now this isn't to say that in reality the aliens didn't sustain any damage, just that it appears to the public that they didn't. Indeed, it might trigger some groups to claim that the attack was entirely a ploy by the government (after all, there would be no hard physical proof of aliens in the city). In short, it would become known as the Phantom Invasion. A symbol of alien power (which opens up the possibility of Phalanx researching the event and eventually discovering that it was staged and that the Aliens can't actually throw such overwhelming might against humans). From what I have gathered, the aliens only have one (or, at any rate, a limited number) of colony ships waiting in the solar system. They have finite resources and as such are actually at a disadvantage to the humans, who have all the power of a race to throw against the invaders.
The aliens know that they don't have the "manpower" to actually occupy the ground, so they have to make the humans think that they have already lost. Basically, the aliens know that humans will win the war by not loosing (that is, as long as humans are around resisting, then we are winning). This can still preserve the feel of an escalating combat system (as with X-Com), where the aliens are trying to establish a foothold with limited resources in order to amass the materials necessary to increase their robotic army, while preserving the original “they’ve bombed m’bai!†color.
Additionally, in this future world, it sounds like the world's military has been left to atrophy. Peacetime generals are incompetent enough as it is, but a fighting force that hasn't seen heavy combat in decades isn't capable of picking it up at the drop of a hat. Add to that the fact that militaries always prepare of the last war (such as France building the world's largest trench system right before WWII) and humans wouldn't really have a hope of a full scale military reaction.
Besides, how does one mobilize a limited fighting force to defend every human settlement? The military would protect major cities, key strategic points, but you'd still need a highly mobile reactionary force to defend everyone else. Thus, Phalanx. It wouldn't be designed to fight a traditional war with the aliens. Indeed, it isn't even David and Goliath syndrome; it would be mosquito and goliath. Phalanx wouldn't see that it has the ability of actually defeating the enemy, but it could distract it enough so as to give humanity time to think of something. They don’t plan to drive the aliens back by brawn but rather by brain.
Since it was brought up, in this world of 2084 where peace rules doubleplusgood, wouldn't all nuclear weapons have been disarmed and stored? Indeed, even assuming some of them could be rearmed, they would be in such a sorry state of condition that they would be more of a threat to humans trying to use them than Aliens. Depending on if Fission power is even still used, producing more nuclear warheads could take such resources and time as to be totally impractical.
As for Phalanx itself, if it was up against such an overwhelming enemy, it seems like its goal wouldn't be so much as to defeat the enemy, but to find out how to beat the enemy (different focus). This does include protecting innocents from terror attacks and preventing governments from being infiltrated (in classic X-Com style) but each action is taken with the intent of determining enemy weaknesses, not so much killing the enemies. Indeed, I would expect that as soon as Phalanx discovers new technology that that information would be passed along to the military and that it would see all sorts of field action. Some people have wondered about its role in the world prior. Perhaps I missed it, but why should it even exist prior? Some form of it is good, perhaps the U.N. had passed the "Phalanx Protocols" decades ago but they were never implemented (like so many UN resolutions). After the attack on Mumbai, or maybe after the first alien appearance 3 days earlier, the Phalanx Protocols were thrown into effect. Within hours, certainly within days, a commander had been selected and it began to operate out of established military bases until its own structures could be built. Since after the Mumbai incident humanity would need a morale boost, whoever Phalanx reports to wanted a symbolic victory and fast. That commander failed and was replaced (sort of like in the Civil war, with Lincoln going through generals like bread). Thus where the player picks up Phalanx has been in existence for a little while, its first base is ready to be built, but it has yet to score a victory (and the player has to get one soon or fail).
Indeed, since the need for a human victory is so critical, other organizations like Phalanx might be formed by other groups. Perhaps the riches individuals in the world pool their resources to create “X-Com†(as a reference to the spiritual parent of UFO:AI, which should be within fair use laws) or “Ex-Calibur.†Perhaps private states formed similar units to specifically protect their territory. These organizations might occasionally help Phalanx, but they could also be infiltrated (it might be interesting to have missions where the enemies are actually human turncoats).
Curiosity, but how long have the aliens been watching earth? 5,000 years is not old enough (humans had technology well before then). Indeed, Egypt has been “civilized†in one form or another for about 12,000 years. However, f we went with a multi-millennium time line, then were could throw in Chariots of the Gods mythos and include “archeological†missions were Phalanx has to find and retrieve certain alien storage devices hidden in the Sphinx, Pyramids, the Mediterranean, Atlantis, Lemuria, Mu, Aztec temples, Templar Churches, etc. That is, the aliens were here, but they also left information storage devices (as well as other devices of power) that humans can use to further their understanding of the aliens. This would be more than just a single mission or two to establish the Egyptian connection (though a more mythological connection might be advisable, such as Atlantis being a floating alien city or some such, from which they influenced the Egyptians, rather than being in Egypt itself). Sort of like the artifact missions in TFTD, but focusing on search and retrieval rather than search and destroy. Such mission might even open up research avenues, and it might also diversity the sort of people working in Phalanx to include more than just “scientists†and “engineers.†You might need “Historians/Archeologists†to point you in the right direction for finding these artifacts and “Linguists/mathematicians†to crack the alien language and to encrypt your own messages in greater complexity (because the aliens would be trying to do the same, right?)
But as for the aliens finishing “business,†don’t forget that under the Egyptian connection they only made plans with one part of humanity. They might be finishing up business, but they are also taking care of usurpers. Those uppity Greco-Romans, those savage Germanics, Sumeria and Persia, China and the Americas, they aren’t under such a contract. If we want an earlier connection, personally I would recommend a more passive role in human history. They were here to research the planet, find out if it was even worth keeping on their star charts. Besides, from what I have gathered about these aliens, would they have even bothered making a deal with humans? They believe that they are superior, and as such they may well believe that Earth is theirs by divine right and that subservience is the natural state of all other species (including humans). Or perhaps they are all just Xenophobes.
And finally (to make a long, disconnected post longer and more chaotic), in terms of alien technology, would it be possible to design similar but alternate variations on the weapons? One thing I never liked about X-Com was that humans only advanced through mimicry. Oh they got lasers/gauss weapons, but then there were plasma/sonic and for all of humanities supposed creativity, they weren’t improved upon. While human interpretations of weapons (like the above mentioned plasma shotgun or Tachyon bazooka) might be interesting, adjusting weapon stats to fit humans would still be a nice touch. That is, let us say that physically the aliens are fairly weak, thus an alien rifle has to be lighter than a human could carry. As such, it is less powerful. The human version would be more powerful but perhaps the greater power would affect recoil/accuracy. A basic pallet swap would allow for the same models to be used for both but with an easily recognizable difference. Also offers players a little more in terms of choice, “mmm… these aliens are tough, so the Tachyon Rifle H would be nice, but those nasty Crystalides that are with them are just to scary to risk missing… guess I will have to go with the Tachyon Rifle A.â€Â
I do really like XCOMTurcocalypse’s suggestion of a Lovecraftian theme, but I am not sure how we’d even go about implementing it.
Just a,
Thought