HL2 Theories


May 16, 2003
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Okay, I've jumped on the opportunity to create this thread before anyone else ;)

Post your theories on anything HL2 related here, ya? :cheese:

I'll start -

I reckon there could be a fair few sides, The Combine, the New Aliens, the Old Aliens (Headcrabs etc), and maybe another side of the Old Aliens (remember in HL1? The Bullsquid, which will apparantly be back in HL2, hated all the other Aliens), and then of course, Gordon's side, whatever that may be.

Soo.. City 17, a nice peacefull place, untill The Combine come in and take over, with their ground troops (who I believe are a mix between Robotic and Organic matter) and their Mechanicals (Striders, maybe?). I would say that these guys are in league with some of the Aliens, such as the Ant-Lions, but as seen in the Bug-Bait video, that is probably not so, although you could say that the Ant-Lions were stupid enough to be tricked into attacking the Combine Soliders, and they shot back to defend themselves against the crazed beasts, but then theres the huge freaky Ant-Lion at the end, who seems intent on killing everything?

Anyway, they're slowly taking over City 17 using the Black/Grey Tower thingies, which I think is a splitting image of the Zerg's Creep in Starcraft, or the Undeads' Creep thingy in Warcraft.

Heres where my theory goes abit weird - The Combine are not only doing this to earth, but to other dimensions too, such as Xen, since they don't look pretty earth like to me, I figure they are from a different dimension/planet altogether. Somehow, Earth/City 17 (which may be the last remainly place on earth not yet taken over by the Combine, although where the G-Man and his mates are hanging out is beyond me), becomes a massive portal where aliens from all dimensions are pulled into it. This would explain why the sides appear to be against each other, some of the aliens (such as the Ant-Lions) may simply be scared, and thus attack anything that moves, others, such as the Headcrabs, latch on to any civilians/combine they find hanging around and populate the City with Zombies. Some of the smarter aliens, however, team up with the earthlings, aka - Gordon and his friends.

Hmm, so where does Gordon and Mr. G-Man fit into my theory? Uhh, well im not so sure, really...

Well, go on, post your theories guys! :) :)
Well, you beat me too it!:hmph: :hmph:

I'm thinking along the same lines really (see my other post). The G-Man may be truely evil - i.e. he may have taken control of Xen to allow the invasion of an alien force (he may be an alien himself for that matter). On the other hand he may be a decent guy who took Xen in an attempt to launch a strike against an even more formidable threat (who knows what will come through that portal).

The aliens clearly differ in intellegence etc. The houndyes, bullsquids, antlions, etc are not terrbly bright (they have no technology etc.) and just got caught up in this mess and are going about their daily lives on a new world (hunting etc.). The headcrabs are merely a parasitic species. The intelegent species (from the first halflife) are all from Xen and are characterized by a third arm in the middle of their chest (the slaves, controllers, and alien grunts). Xen was of course ruled by Nihalanth (the big bad baby). Remeber that when you first open the portal in half life 1 you briefly visit TWO worlds (one with bullsquids and Xen - the one with slaves). I believe it was hinted at that the new aliens in OP4 were from a third world and arrived on earth after Gordy made the leap to Xen.

In HL2 I suspect we will see a new larger threat, a far more sinister alien race which used Xen as a stepping stone to get to earth. In fact I would not be surprised if we join forces with Zen (and other weaker worlds) to fight off this new universal threat. The Combine, I think, are aliens which are attempting to police City 17. This city is the focus of the upcoming invasion (the alien citadel may house a major portal.

Well, that's my two cents.
Ohh, I just thought of another idea.

I'm sure we've all noticed the strange sky/lighting in the videos from E3, right?

Well, assuming they were not just dodgy recordings or something, doesn't that seem a little, odd, for earth?

Which brings me onto my theory, that working for the G-Man involves something altogether different than defending Earth from an Alien invasion. After all, since when did the G-Man care about the environment? I would continue, saying maybe that by working for the G-Man, you are assaulting another Planet or something, but Gabe Newal said in the Gamespy preview, that the entire game would be set on earth. Still, something must be wrong with Earth if the sky is like that, no?

Also, why on earth does Gordon still use his HEV suit? Sure, it might just be a trademark such as the Crowbar, but maybe there are other reasons..? Or maybe he's trapped in it, it does look a tight fit, doesn't it? :D

And where does Alyx, Eli, and Dr. Kleiner fit into all this?

As much as we can gather from the E3 Videos, Dr. Kleiner is working in-line with Alyx, and maybe Mr. Freeman, in the Video, he seems to be working on something, but what? Alyx also notes that she wants vengence against the Combine for something they did in the past, hmm... Apparantly 15 years or something has passed since Black Mesa, I'm guessing the Combine did something during that time, which let up to here.

Also, during that video, it's hard to tell, but is that multi-coloured strobe lighting, evident in nearly all the other videos, gone?

Hmm, watched it again, Alyx says.. "I'm sorry Gordon, I can't help thinking that this isn't going to work, we should have listenend to my father and done it his way, it's just, this is the first time i've had any chance of striking back at the Combine."

Hmm, whatever could she mean? Maybe the Combine had some unseen relation to the Black Mesa Incident?

And don't forget about the Black Ops/Assasins, where do they fit in to all this? Most people (including myself) pinned them down to working for the G-Man, to clean up the Scientists and the Grunts.

I was playing Op4 this morning, at the bit in the vent when you first see the Black Ops, talking quietly next to a truck, I can't remember their exact words, but it was something like, "Why do we always have to clean up the mess the Grunts can't handle?" Hmm, interesting, no? But of course, they were Gearboxes creation, and may not have any relation with Valves storyline.

Anyway, back to Alyx's quote. Why could she want vengance against the Combine? I first thought they may have been responsable for her Mothers death, but in multiple previews it's been stated she was killed during the Black Mesa Incident, but, who knows? That may simply be more proof that the Combine have some relation to that incident.

Back to the scene, Dr. Kleiner talks about various things, with quotes like "Conditions could hardly be more ideal.", you start to get the picture that he may be setting up some kind of teleporter.

Well, im pretty tired now, I'll add to this tommorow.

[ Note : Wouldn't it be funny if Valve made all these E3 Videos up, with no relation to the actual HL2 storyline? :cheese: ]
I should mention the significance of Xen. It seems to me that Xen is 'a major node on the portal system'. i.e. the portals between the various worlds appear to converge on Xen (perhaps because it is home to those funky crystals - the so-called "anomolous material")
Because of the dried up sea-floor setting, I assume something has gone wrong with the Earth's climate. Global warming is the most likely culprit.....however that should raise the sea level rather than lower it (due to the melting of the ice caps).
With regard to Bullsquids, I just assumed they were animals. After all, not all life forms on this planet are particularly enamoured with homo sapiens.
It was a dodgy camera that changed the sky, which was very cloudy but not overcast. Also, I think the wasteland and the pier of City 17 are two different locations. If you listen to Gabe in the last of the 8set movies he says you're back in City 17, meaning it was a different location. I haven't heard anyone post on the ship yet though.
Chthonic - That is an excellent point!

Hmm, just made me think of something else..

As Calm_Blue_Ocean said, about the teleporting to Xen during the intro in HL1. The Bullsquids you see don't attempt to attack you at all, they ignore you. As do the Alien Slaves.

This has probably been said before, but I think thats some proof that Xen Aliens are not out to start war with Earth at all. They are transported there, attacked by all humans, and retaliate.

I found a very good article whilst searching around the net on this theory, and here's a chunk which explains my previous paragraph -


XEN. 9:00AM, May 15, 1995. (Earth Time)

A bipedal creature loped down a slight embankment towards a stream, in the back-ground the temple stood silhouetted against the pastel sky. The gentle, almost inaudible sound of prayer filled the still sky. Nearing the stream the creature slowed to a halt and looked around. Something, else was near, it could sense it.

In a flash it was catapulted in to another world.

Experimental Teleportation Lab, 9:01AM, May 15, 1995

Disorientated it looked around at the harsh landscape around it, where was he? This was not home, what had happened? All around him figures, smaller than he was rushed around. They pointed and shouted in their crude languages. Confused he moved towards one, calling out for some explanation.

Behind him a figure dressed in blue ran in to the room and gave a harsh call and opened fire. He could feel a burning feeling in his back, and he turned and saw the figure for a moment before his eye exploded with pain. Falling, limp and broken he gave out a call for his homeland, for his family, and most of all: His god.


Interesting stuff, huh? Catch the entire thing here.
Yeah, your right about the sky being down to a dodgy camera, the Gamespy 500mb E3 Video has a proper sky, which still looks a lil eeree ;)

I reckon alot of the game will be outside/on the outskirts of City 17.

I'd also like to add, that I think the weird flying laser-shooting thing with the propellor at the back end of it, is another Mechanical thing controlled by the Combine, I say this, because on the dune-buggy video, as far as I can tell, it never attacks the Combine soliders littered around the map. Although it may just be seeking out one target, the soliders don't seem to attack it either, which they would usually do based on their apparant AI.
Good point about the 'flying mechanical manatee' Dave. And yup, that's what I meant in reference to the bullsquid - it's basically just a predator looking to protect itself and probably looking for food. That was what was great with halflife, not all the aliens had agendas, many were just trying to make due with the new environment they accidently found themselves in (and reacting with the appropriate level of intelegence). If I remeber correctly from playing around with the editor, the bullsquid attacks anything, including other bullsquids. The houndeyes were also really cool in this respect, it will be a shame if they don't return (and just imagine them with the new engine - one giant glistening eye, or perhaps several, watching your every move). Houndeyes were also pack animals, they were more aggresive in groups and attcked anything except other houndeyes.

I always figured the black-ops were added mainly to provide a human opponent for OP4. It seems the government sent in the military to clean up, and then later the G-Man sent in the black-ops to clean up the military.
Ahh yes, but why would the G-Man do that? Personally, I think Half-Life's script writer is a genius. I'm sure he planned most of HL2 and maybe 3 when he wrote the script for HL1. It'l probably be something none of us ever expected, ooh, I can't wait! :cheese:

Also - I've just been looking at some screenshots. Assuming they're not all made up promotional shots with no relavance to the game, http://hl2hc.halflife.org/pics/screenshots/Halflife00.jpg seems to show that the Combine are definatly not in league with the Ant-Lions.
I like your theories

check out the symbol on the back of the strider.....(combine)...
I reckon the combine are some kind of bio-mech culture. The flying manatee, striders and troopers all seem to be semi-mechanical in part (hence 'combine'?).

In HL1 it became pretty obvious that some groups at Black Mesa had been experimenting on Xen lifeforms for some time before the test (re:Questionable Ethics, the first Icthysaur encounter). When the resonance cascade happened it opened up a huge rift between the border dimension (Xen) and Earth, so the aliens there took the opportunity to come through and take out the people responsible for kidnapping them (semi-defensive reasons but invasion was also the name of the game). With the sentient Xen parasitic culture (headcrabs -> zombies -> slaves? + hornetgun soldiers, gargs, etc) also came some of their animal life like bullsquids, houndeyes, snarks, icthysaurs, barnacles, caught up in that same rift... Xen being the dimension between worlds they probably just got randomly teleported in when the rift was opened permanently to Earth (and held open by the Nihilanth).

It was the administrator who ordered the test to go ahead that first day, so he/it; a) probably knew what was going to happen, b) wanted the nihilanth dead so he could assume control of Xen, and c) wanted the resulting war for some as yet unexplained future (HL2) reason -- besides the destruction of Black mesa remember the shots of destroyed tanks in Xen? Looks like he had the human troops invading Xen as well at some point. Maybe the stuff at Black Mesa was just a sideshow to the G-Man's pre-planned invasion of Xen, and he used Gordan as an assassin to kill the Nihilanth and end it ASAP -- the Xen forces' command was pretty much centralised in the big baby and I can't imagine they'ed be able to fight on without him.

As for the Combine? They're from a second world (maybe the one the Xen aliens originated on given some similarities?) and are just moving in on wherever City17 happens to be -- which could be a third dimension/world? That it looks so similar to Earth might indicate they're parallel worlds, with the Antlions, hydras being native to this one. That or some soviet group got there ahead of the Black Mesa crew and built the eastern european looking city (Stargate like plot). :)
The alien slaves are your allies now. this was said in a Game magazine article (PC-ZONE benelux) I believe.
Snark^, Good ideas, but in the Gamespy preview Gabe Newal stated that the entire game would be set on earth.

Also, Ghostrider was absolutly right, Combine Soliders and Striders, and maybe the Flying Gismo Laser-Shooting thing, have the Combine logo on them. I think they are definatly robot like creations made by the Combine to aid them in taking over City 17 (and perhaps other places).

As for the Alien Slaves being our allies, I read that too, shows that the Combine might be invading Xen also, or worse, already invaded it. The last remaining Xen aliens may be back on earth for the "Final Battle" against the Combine.

Whats really bugging me is what Alyx has against the Combine.. Hmm..
the combine are biomech aliens, just like the helicopters and the fleying blade thingies and the striders.. and we will see alot more.

I think the combine are in war with the Xen aliens. and they are fighting the battle on earth. and they are slowly taking over City 17 with thier barrier wall. but i dont know how you - Gorden Freeman - and the g-man are involved in this

anyway.. I think this means that the story isnt an easy one.. and it will be very good, totally suprising you. I am wondering how Halflife 3 will be.
Hwo are those guys with white masks and Assult rifles ??
And those white people how runs over the street in video 8 from GS, and meets the strider... Are they militias from City 17 coz they dont act like any soldiers...
Well couldn't the term combime mean that they mixed human and Xen tecnology and got the striders an flying thing?? it would then make sence that both humans and zen dont like them....
Did anyone else notice that in the "teaser trailer", that when the flying things were in the city the two people standing near the APC were frozen in mid stance? Do the flying things stop time (like in the movie clockstoppers) or was that just an incomplete demo?
I think that they were some sort of Combine scanner drones....
Originally posted by Cleric
Well couldn't the term combime mean that they mixed human and Xen tecnology and got the striders an flying thing?? it would then make sence that both humans and zen dont like them....

Good idea, we're getting somewhere - Dictionary.com definition of Combine -

1. To bring into a state of unity; merge.
2. To join (two or more substances) to make a single substance, such as a chemical compound; mix.

Evidence shows they are likely to me a mix of something now, but what?

I thought of a way Gordon and co. could fit into this -

The G-Man is very sinister, he's constantly meddling with various dimensions, but I think he is an Earthling (despite his bulletproof skin in HL1 ;)).

Anyway, the G-Man snatches up Gordon after his performance in the Black Mesa Incident, and uh, then it gets vague.

He may have teleported Gordon into the future, where the earth is under attack by all these different forces, which would account for why he is still wearing his HEV suit. But then, how would Barney and co. get there?

Still going with the teleport idea, Mr. Smart G-Man could have teleported the entire population of Black Mesa to this future place, which would account for the remaining Slaves, Headrabs, Zombies, etc, as well as Barney, Dr. Eli and Dr. Kleiner, and Alyx?

Thats a bit of a longshot, it's far more likely that the time passed in real-time, or even continues directly on from HL1 (which would also account for Gordon's HEV suit).

However, although Gabe stated that the entire game would be set on Earth, that doesn't necessarally mean the same dimension, right?

Maybe Black Mesa was a big weird dimension twisting thing, when the event was finnally over, everyone and everything in Black Mesa, was in another dimension (it's still Earth though, technically). Naturally the G-Man knows all this, and was constantly dimension-hopping.

Theres just so many theories for this! :)
It would be cool if Valve visited this site and lafed at us for our ides *ha ha ha*

We can only guess !!
In video number 8, the man who comments on the video(guess it is someone from the valve team), states that the Zitadel is slowly eating or expanding over city 17.
Originally posted by CDQ2
In video number 8, the man who comments on the video(guess it is someone from the valve team), states that the Zitadel is slowly eating or expanding over city 17.

yeah i know its like they are sucking up the city from above..maybe they are here with a huge mothership this time :)
I remember seeing somewhere (can't recall exactly where given the recent info glut: gaming sites, fan sites, preview articles, alt.games.half-life) that someone reckoned the tall building behind the creeping wall was a space elevator. Could the final levels involve taking it to the combine in orbit? (combat in zero-gee physics?) Would be cool. :D
Was it at the end of Half Life or OpFor that the G-Man said Black Mesa would no longer be a problem? (You see the white flash of a nuke going off). As mentioned above, Xen contains the yellow crystals that start the whole Black Mesa disaster off. Perhaps the Combine (I'm not entirely sure who they are :eek:) is another dimension trying to gain control of Xen for the crystals, but since the G-Man already accidentally came into control of it (Gordon Freeman having killed the Nihilanth), the Combine are now invading Earth to destroy human links to Xen.
hmm.. nice ideah.. but i dont relly like the fact of batteling in orbit.
IMO I think that the walls that are "eating" city 17 is gathering materials to build the tower.. maby the invasion is still going, and a spaceship has crashed @ city 17, in one of the dune (the one with the 2 ant lions @ the front) pics you see a wreck maby thats thier ship and now they have taken over city 17 and building a tower for a teleport or something like that (one of the pics in one of the magazines sait that it was called teleport.) so maby the combine are in war with the xen aliens and came to earth to blast the earth because there are xen creatures ther, but the ship crashed and now they are building this tower so they can get home when they have destroied the invasion on earth.
you arent allied with the aliens.. the vid with the ant-lions just shows that you can fool them into helping you.. he uses some kind of scent bombs to tell them where to go.. also freeman is covered in pheromons that makes the ant-lions think hes a alien guard, or commander if you will (this is what the guy from valve sais in one of the videos)

and i think youre all making it way to complicated..
the combine is just like the government forces in hl1, another side to the conflict..
since they speak english and do look very human, i dont understand how you can think they are aliens?

and the strider is a alien "tank" and the flying thing is a combine flying vessel

pretty easy.. i could be wrong but thats the way i think it is
they arent tanks and they arent ships, they are "BIOMECHA ALIENS" thay said that in the pcgamer scans i think, or in any of them. The combine arent goverment special ops if you look @ the concept art, you see a alien language printed on thier uniforms. they are alien, and the freedom fighters are fighting the combine becase they are eating the city... cmon.. i know i am soo close

the combine and the Xen aliens are enemy's, the freedom force is fighting the combine because they invade the city etc.. and mr gordon is on the freedom force's side fighting the combine and the xen alines at the same time, therefore the aliens fight the combine first (visa versa) and when anyone of them have killed the enemy they go fight you.

its al more then logic, why in the hell would the combine (in your eyes govement ops) build wierd alien shaped tanks and helicopters (again in your eyes :D). it doesnt seams logic @ all.
yeah but on the other hand, if you look at the concept drawings, the combine troops are using very "earthy" weapons like m16 and such.. if they were aliens dont you they would use some alienlike weapon?..
the writing on their clothes could be some markings they use, like their grades or something
hey stop adding stuff to your post, it makes it harder to reply to :)

i think you have got the vid where freeman fights alongside aliens completly wrong.. the aliens he fights with are lower standing aliens and are controled couse they think freeman is their leader.. but the big alien at the end is not low grade so he attacks freeman.. he/she/it isnt as stupid as the lower grade aliens

and the alienlike construction of the flying vessel (i still think the strider is alien) could be beacause its way in the future.. they build more sleek vessels because they are more advanced then we are today
and if it where an alien vessel, whouldnt it use something else then a helicopterlike construction to keep it in the air?.. that doesnt seem very alien does it?
Both the Strider and the Combine soliders have the same Logo printed on to them.

Sure, the Combine look fairly human, but look at the strange marking on their clothing. It looks like complex Algebra, perhaps evidence to prove that this race, if not human, is very advanced indeed.

Also worth noting, the Combine Soldiers have the number 890 printed on to their backs. What could be meant by that? Surely if their language is full of strangly formed symbols, it would be out of place to use English numbers?

Also, has anyone wondered why the heck they are wearing gas masks? It seems pretty obvious to me that they are not Earthlings. They're faces are always completely covered up, giving the impression that they are in fact invading Earth, slowly taking it over using the Black Towers, and require a filtration gas mask to breath in our environment.
yeah i think theres lots of strange things goin on with the combine troops..
having looked a bit more closely at a screenshot of a strider i know see that it and the flying vessel has some very similar designs
like the mounts to their canons

so based on that, it seems as the strider and the helicopter thingy are both combine

the thing with the gasmask could be just because they should be easy recognisable from the freedom troops.. just a designchoise from valve
and it do make them look more sinister

perhaps the combine are humans who have borrowed technology from the aliens?

They speak English, they have numbers on their backs, they carry weapons made by Heckler and Koch, they move like humans, they wear Russian gask masks! The only evidence that suggests they aren't human is the "writing" on their uniforms(has anyone actually seen this in the videos or was it just in the concept art) which could be written for computer scanners or something.
i completly agree Belisarius
i think it is a bit far-fetched to think they are aliens..
tho they, as i said, could very well have borrowed alien technolgy
Who said they were Aliens? I was simply hinting that they could be from another Planet or Dimension. If it's the latter, they don't necessarally have to be Aliens, and they could talk English.

On the subject, I thought of another theory.

Alyx, her father and Dr. Kleiner are part of the City 17 Resistance (with the guys you see hanging around getting beaten up by the Combine Soliders. This would account for Alyx's hatred for the Combine, quite possibly they may have destroyed her home, family members, etc..

Anyway, the Combine Soliders are elite soliders under the G-Mans orders. Naturally, he want's to rule the world. So what better way to do it than cover it in Black Metallic Towers? But he's not content with ruling only Earth, he may or may not have already taken over various other planets/dimensions, such as Xen. Using the resources there for his own use.

Now, Gordon was employed by the G-Man, right? The G-Man noticed his natural skill as a solider and rectruited him to work in league with the Combine Soliders, maybe as a squad leader or something.

This screenshot is what i'm basing most of this theory on. Assuming the Combine Solider isn't too caught up with the Ant-Lions to notice Gordon, or that this sequence wasn't specially made for screenshot purposes (yes, I know it's not fully textured..), then maybe this could be from early in the game, where Gordon is working alongside the Combine Soliders, having no other choice.

Then he meets up with Alyx and the surviving Scientists, gets rid of his Combine Armour and equips a HEV suit, given to Gordon by one of the scientists (most likely Dr. Kleiner). Of course, it might be a new version invented by Dr. Eli himself

Anyway, from this point on, Combine Soliders (and Mechanicals) attempt to kill him, since he is now part of the resistance, with Alyx as his [sidekick?]. They attempt to rid City 17 (the last "free" city on Earth) of the Combine.

The reason the Aliens are there, too, is because with all the planet/dimension skipping the Combine's are doing, Aliens from all different planets/dimensions can freely walk into one another.
Combined: mecha-Xen, mecha-human, Xen-human, or even all 3 -- I'm betting mecha-something given their seemingly bio-mechanical nature. Maybe the Combine ground troops are humans who've been taken and 'altered' to suit Combine needs. Maybe G-Man created and runs the combine -- they're his force after the events of HL1 (I've never seen him as a good guy).

PC Gamer had the first scoop on HL2 and they ran a couple of theories in their preview: first one was that the earth has been overrun and the resistence holed up in Eastern Europe (no city in the old warsaw pact areas called it self by number though) -- second theory went with a twist where this is set on another world that's merely similar to Earth -- eventually Gordon realises the aliens are just defending themselves and "naturally switches sides midway through the game".
What I find interesting is that the Combine are arresting alot of the humans in City-17 instead of outright killing them.
could it be that the striders and the flying baddies are origanal combine tech but they also have the ability to take over human bodies or install some kind of mind controll?? kinda like the borg or something....