Wow, Wall-o-text. When i first started this, I had intended for it to be a short post. But once i start, I can’t stop. Thats why i try to avoid this thread as much as possible.
If I recall correctly, the combine want to create another Black Mesa like incident in order for their off world forces to be able to punch a hole back through and overwhelm the resistance once again.
I think that then ending of Episode 3 will definitely set up for HL3, and that this is perhaps one of the reasons that it is taking so long, is because they are also thinking about HL3 and deciding on how they want to proceed. Most likely in Episode 3 the Gman’s plot will be reveal at least partially, and that he will become the main antagonist of HL3. Remember that after HL1, the Gman’s forces were left in control of Xen, and that it was one of the few places that the combine can’t reach. The perfect place to begin building up one’s forces and preparing for an invasion.
Now I’m sure that Alyx will play a pivotal roll in the main plot of Episode 3 based on the significance placed on her by both the gman and the vorts. Since the Borealis has experimental portal tech similar to Black Mesa and is capable of creating another resonance cascade, I am going to guess that the ship will go on the verge of a resonance cascade. Since the previous resonance cascade opened up a hole to Xen, the Gman may want Alyx to trigger another cascade tearing open a hole to xen which they can exploit and release the build up of gman’s forces laying in wait to invade and wipe out the combine completely. Gman has shown that he has the ability to control Alyx’s behavior; he may program her to activate a resonance cascade right at the very end.
I think that Episode 3 will be like Star Wars 3: Revenge of the Sith. The real major villan will be revealed, and will triumph at the end of the episode and drive his enemies to the bring of extinction. Then in the sequel time has passed, Gordon (and maybe Alyx) has returned in the future, thanks to the vorts, and Gordon’s job will be to defeat the Gman.
I think that The Universal Union and the Combine aren’t that synonymous. I think its something like the EU; different sovereign countries that share ties with each other, except the UU has more government powers. I think that the UU is something of a universal ruling body that’s primary political party is the combine, and that the Gman is “working” for a rival faction, his employers, who will attempt and succeed in a coup d’état of the UU and wipe out their rivals the combine. Something like the Old republic becoming the Galactic imperium. But since the Gman has shown his lack of regard for his employer’s orders and his ability to know more than they do (i.e. about Alyx) I think that he will also stab his employers in the back and usurp authority for himself.
Remember the Combine story arc is over after this episode. Now in HL2 all they have done is defeated the forces of the combine on Earth, but there are many more planets and dimension under their control that could easily wipe them out if given a chance. Now either their ability to make it back to earth is permanently sealed off, thus removing the threat of the combine and closing the arc, or the combine is completely annihilated, something that only the gman would perhaps be capable of. We know he is planning something big, and this may just be it. Also remember there has to be a cliffhanger for HL3 or something that opens the door for the plot of HL3.