I'm not sure if I'm an idiot or if it's because English is not my native language or what, but I find it really difficult to follow this narration style.
Can someone give a short summary of what happened?
They go to Antarctica to find the Borealis (the ship built by Aperture Science from Portal).
The Borealis is phasing in and out of reality. Rescue Dr Mossman from the Combine, she has details to make the Borealis phase in for enough time to get Freeman+Alyx+Mossman on board, chased by Combine.
While on board, discover Borealis is moving through Time as well as Space. Mossman wants Borealis recovered for the Resistance, Alyx wants it destroyed. They fight, Alyx kills Mossman.
Borealis reconfigured to fly through Space to Combine planet to try to destroy it with explosion, as they arrive G-man takes Alyx off the ship, Vortigaunts take Freeman.
Combine world too massive, powered by a Dyson sphere, Borealis explosion does nothing.
Freeman back on Earth sometime in the future, won't take part in any more conflict with Combine.
I haven't played the game, so I'm a bit confused: what parts of the story are slyly referring to Valve itself rather than the HL3 story? How do you get "welp, looks like HL3 is cancelled" based on this story?
The last paragraph is almost definitely about Valve:
"And here we are. I spoke of my return to this shore. It has been a circuitous path to lands I once knew, and surprising to see how much the terrain has changed. Enough time has passed that few remember me, or what I was saying when last I spoke, or what precisely we hoped to accomplish. At this point, the resistance will have failed or succeeded, no thanks to me. Old friends have been silenced, or fallen by the wayside. I no longer know or recognize most members of the research team, though I believe the spirit of rebellion still persists. I expect you know better than I the appropriate course of action, and I leave you to it. Expect no further correspondence from me regarding these matters; this is my final episode."
No more HL2:Episode N coming, the development team is too different.
The boat mentioned during HL2 E2 can teleport anywhere easily and instantly. The crew set it teleport to random places so the aliens wouldn't get it. Gordon and Alyx are able to board the boat, where Judith Mossman wants to use the technology to help the resistance while Alyx wants to destroy it as Eli wished. Alyx kills Judith and rigs the boat to explode. Her and Gordon teleport to the alien homeworld on a suicide mission. Alyx is recruited by the G-man and Gordon is rescued by the Vortigaunts. The boat bomb is much too small to damage or destroy the alien planet. Gordon awakens on an Earth where much time has passed.
- Freeman and Alyx Vance, acting as an advance party for a larger Resistance force, seek out Borealis, the Aperture Science research ship which Eli Vance charged them to find and destroy shortly before his death. Their helicopter crashes near the site, and they make the last few miles (?) by probably somewhat frostbitten foot.
- On reaching the location in Antarctica where Borealis is last known to have been, Freeman and Vance find the ship is phasing in and out of spacetime, and a Combine garrison has been established to capture it at earliest opportunity. They also find a surprisingly alive Wallace Breen and kill him, and a captive Judith Mossman who, despite her earlier actions painting her as a Combine quisling, insists she's actually a Resistance double agent. She also has the plot coupon required to access Borealis. Freeman and Vance break her out and bring her along.
- The party succeeds in boarding Borealis, as do some of the Combine troops from the garrison. The ship immediately desynchronizes from local spacetime again, both isolating the boarding parties from the Combine and the now-arriving Resistance forces, and exposing them to severe disorientation as distant times and places impinge upon the tenuous reality aboard the ship.
- Borealis's situation proves to be caused by an incomplete long-distance teleportation system, the "Bootstrap Device", which was being developed aboard the ship prior to the Combine invasion. As Combine forces seized the graving dock which housed Borealis during the Bootstrap Device's development, the science team on board favored the possibility of escape over the certainty of capture, and activated the untested Device with a target destination of Antarctica. It sort of worked, but left Borealis unstuck in spacetime. The fate of the science team is unknown.
- Two options emerge for what to do with Borealis. Mossman favors permanent resynchronization with the ship's destination spacetime, allowing the Resistance to study and exploit the technology aboard. Vance favors rigging the ship's reactor (or something) to explode, and synchronizing her with the major Combine military staging area that's been a recurrent feature of her shifts through spacetime - thus fulfilling Eli Vance's final instructions and likely achieving an immediate and significant strategic victory, at the cost of whatever longer-term benefit the ship's unique technology could offer. Mossman attempts to disable Vance and implement the former option; Vance shoots Mossman dead and implements the latter.
- The G-man rescues Vance, but leaves behind Freeman, for whom it appears he has no further use. The Vortigaunts rescue Freeman immediately before Borealis materializes in the middle of the Combine base, which is gigantic on a previously unappreciated scale, and the ship explodes to no meaningful effect whatsoever.
Here the plot ends, and Freeman's story - or at least our involvement therein - apparently with it.
Chuck "SFDebris" Sonnenburg made a great point about this in his review of Carpenter's Prince of Darkness: time travel is the ultimate gamble, because you don't know and can't control how it is going to come out. It's the thing you only do when literally anything else is preferable to the status quo. I don't think the situation of humanity at the end of Episode 2 meets that standard. It's bad, sure! But there are countably infinite ways in which it could be much worse.
Can someone give a short summary of what happened?
TD;CU (too dumb, can't understand).