I agree with the storyline critique: if the aliens are *overtly* attacking the world, then there won't be some tiny, secretive unit fighting them. We need a *covert* attack that is receiving a *covert* response by governments.
So, why a covert response? I, too, like the idea of it being fear of global economic chaos that leads them to hide this. Another motive could possibly be fears that large-scale preparations to combat aliens would be taken as a "invade now!" sign, but having alien ships taken out by small squads could be interpreted as anomalous local military actions or perhaps even have the alien commanders doubt humans were involved in the loss of the crew. I.e., the goal of humanity would be to recover enough alien technology and be able to mass-produce it *before* the aliens catch on that we're preparing.
One complication: you're tasked to *save* civilians, yet they're walking leaks. I think this requires a "Men in Black" style memory wipe for it to be plausible. Perhaps not a complete memory wipe, but more something like blurring/damaging their short-term memories so that they'll doubt what they think they saw and be more likely to believe what they were told (meanwhile, a cleanup crew tries to undo the damage).
Of course, you need a motive for the aliens -- and not that they're "evil"! They need to see us as a long-term thread to their existence. So, perhaps a machinma (acted out by 3d models in a gaming engine) opening of:
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SCENE: Darkened science laboratory; computer screens and LEDs are the only things visible. A sudden flash like a laser weapon illuminates the scene, then settles down into a soft blue glow; you can see some sort of strange reactor taking up most of a large room.
Voiceover: "It was our finest hour. Who would have guessed, after the economic disaster trying to harness fusion at DEMO, that such a simple solution to powering our dreams was within reach: zero point energy, power from the fabric of space. It was almost too good to be true.
SCENE: As the text proceeds, the reactor dims, turning the room back to blackness. In from the blackness shine stars, and we see an alien spacecraft headed toward a strange planet. On the surface of the planet, sickly column of flame rises beyond the atmosphere
Voiceover: "It was."
SCENE: The spaceship shown previously lands on the surface in a hellscape. Alien bodies lie everywhere. Buildings are torn apart. Trees are snapped off and all aligned in one direction from a massive blastwave. Heat shadows are burned into the surface from objects half-sheltering what was behind them -- bridge pillars, trees, bodies all burned into the ground like sick artwork. In the distance, the columns of flame still shoot up from the ground as the aliens step out of their ship to survey the destruction.
Voiceover: "Our new technology was our godsend, and our economy grew addicted to it a heartbeat. But our blessing was their hell. The Arcturan's planet had the misfortune of orbitting through a mirror node to ours, and the disruption of the fabric of space that we bled power from ripped apart their world time and time again."
SCENE: The lead alien surveying the scene raises an arm to the air and screams in an otherworldly voice. The image fades out and fades in, looking up at a 3d hologram of a human woman standing at a podium. She continues, in the same voice as the voiceover.
Woman: "This was our doing. They have every reason in the world to want to destroy us, or worse, and God help us, they're getting ready to."
SCENE: The view changes and you can see that the woman is speaking before some sort of futuristic teleconference with two dozen attendees; all but one person is holographic. The non-holographic person wears a PHALANX military uniform and sits at a separate table by her side. Everyone else appears to be a high ranking official of some sort from all over the world and is gathered around an oval-shaped table. On a screen behind the woman, you see a blurry image of a spacecraft headed over earth.
Woman: "SIGUR-8 captured this image of an unknown craft entering earth's atmosphere last Thursday at 14:21 GMT."
SCENE: The crowd murmurs. The woman makes a hand gesture at the screen and the image. Behind her, you can see a scene of dead civilians scattered around a damaged building. The murmurs fall to dead silence.
Woman: "This is Selengee, Mongolia, the following day. There were no survivors."
SCENE: The camera changes again. The woman gestures repeatedly, flipping through pictures.
Woman: "Notice the entrance wound here. From what we understand, this was done by plasma, fired in a beam at chest level." (Waves) "We're not sure what caused this, but whatever it is, it makes our best weapons seem like toys by comparison."
Holographic Politician Man: "What was the point of this? Terror?"
Woman: "They only recovered the bodies of twelve individuals. Three are missing and presumed to have been abducted."
SCENE: The crowd has trouble taking in the scene. A holographic politician leans foward.
Holographic Politician Man: "They're studying us. They know nothing about us, who, we are, what we can do."
Military Man: "Most probably."
Woman: "However, they will, soon."
SCENE: Camera changes to a holographic woman wearing politician clothes.
Holographic Politician Woman: "Then we need all of our forces on high alert. We need to collectively deploy everything we have in order. . ."
Military Man: "Yes, make them think that they have to act now? Destroy the economy with worldwide terror? Is that the plan?"
Holographic Politicial Woman: (beat) "Then what? Do we just let them kill us?"
Holographic Political Man 2: "We can try to negotiate. If we learn to live without power, yes it will take years to rebuild,"
Holographic Political Woman 2: "Negotiate? We incinerated their homeworld!"
Holographic Political Man 2: "You want to fight a losing. . ."
Woman: "Everyone! With your blessing, and your funding, we will combat them with their own technology. We will avoid leaking what is going on by cleaning up attacked sites and suppressing the memories of witnesses. In short, we hope to prepare for war without letting the Arcturans know that we are preparing."
SCENE: Camera changes to the man sitting next to her. He rises and gestures at the screen. A 3d "PHALANX" logo appears.
Military Man: "Allow me to introduce the Greater European Union's planetary defense proposal. . . PHALANX."
SCENE: The camera flies over his head and moves toward the screen until the PHALANX logo takes up the entire scene. Light flashes behind it, and the camera "lands" atop the 3d shape so that it spreads out in front of the camera like ground, beneath a starry sky. With a flash, a pillar of fire rises in the distance with a sickly red glow. The words "UFO: Alien Invasion" appear and hover in the sky as, from the horizon, angry aliens race in, guns drawn, charging the camera. They attack it and the image disappears. The game begins.
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Modelling work needed for the intro:
With only a few scenes, it should be relatively simple.
First scene: Energy laboratory
Needed: Computers, scientists (we already have models), reactor, miscellaneous equipment (mostly just texture work, as lab equipment tends to be made of geometric shapes)
Second scene: Burning alien planet
Needed: Alien spacecraft (already have), planet (many ways to create; doesn't even actually need to be 3d since it's so big), "devastation" effects (animated columns of flame, reddish clouds and smoke, etc)
Third scene: Alien planet surface
Needed: Aliens (already have), Landed spacecraft (already have), planet surface, dead aliens (already have), planet surface debris of all kinds, "devestation" effects from the previous scene.
Fourth scene: Conference
Needed: Conference room (simple and high-tech looking). Podium. Table. Seats (already have). People (have models, but need clothes). Empty screen. Misc room decor, but not much.
Picture1: Satellite image of earth (3d not needed), alien spacecraft, airbrushed reentry flames.
Picture2: Dead civilian model (have), airbrushed to have wounds and hide 3d flaws; broken building in background.
Picture 3: Like picture 2.
Picture 4, 5, etc: Possible, but not necessary, more pictures of the same scene to flip through.
PHALANX Logo: 3d model.
UFO AI Text: Preferably 3d, made from a font.
Last scene: All components created previously.