Apparently, something gruesome happens to Alyx

Meh. It's rather underwhelming. It only took me about 3 hours to finish, and the only new thing in the game are the zombines. Which are basically just regular zombies but sturdier, they can run, and they might pull out and hold onto a grenade. No crab or mortar synths. ;_; And crap, the final boss is a fucking strider. I feel gypped.

The most interesting parts, by far, are the intro with the G-man and vortigaunts, and the ending movie that seems to indicate Alyx's death and reveals a new, "mini-strider-like" enemy.

On the bright side, at least, while I despised the portions of Half-Life 2 that you had to travel with Alyx because of her incompetence, she's much more capable of taking care of herself and helping you out in combat in this game.

I'll go into depth about the intro movie, since it's one of the more interesting parts of the game:

First, you see a freeze-frame of Alyx and the explosion of the portal. But then a bunch of oddly-colored, glowing vortigaunts start appearing all around her, chanting; then they grab her and disappear. Cut to black, and the G-man walks out of a bright white door, like usual, close up on his face. But before he can say anything, you hear the same chanting, and a blue glow illuminates his face. He looks around, slightly worried, then the camera pulls back to show he's surrounded by vortigaunts. "We'll see about that," he says, as two vortigaunts grab you and everything goes black.

Next thing you know, DOG is digging you out of rubble, and Alyx is there too. You talk to Dr. Kleiner and Dr. Vance on some tv communicator thing, and they inform you that the only way to make it out of the city in time is to go back into the Citadel and stabilize the reactor.

That you and Alyx do, and it plays much like the final chapters of HL2. You even get the super gravity gun again, temporarily, but lose it for no apparent reason when the reactor stabilizes. Another point of interest is when you pass by an escaping Combine Advisor, who does some funky psychic thing on you that has no effect. Around the same time, Alyx also finds some important information file on a terminal and makes a copy of it - but it can't be read until you escape and decrypt it.

After that you find your way to a stalker train leaving the city, but unfortunately it crashes and you have to make it out on foot. You're still underground for a while, and there's lots o' zombies.

After making it back to the surface, you work your way through the city for a while until you meet up with Barney, who needs your help to get a bunch of citizens from a safe house to a secured train station. After taking 5 or 6 or so teams of them across, they load up with Barney and head in one direction, while you and Alyx plan to take a train in a different direction to lead the Combine away (since you've still got the important information they don't want you getting away with.)

This is all well and good, until while you're holding a gate open for Alyx, a strider shows up and destroys the crank. So you have to make your way up and across the station on cargo containters, where you find a box of rockets. Kill the strider, hop down, and get on the train with Alyx. As you make your way out of the city on it, first a bunch of Combine Advisors fly off from the Citadel and do their psychic thing on you as they pass. Then the Citadel explodes, and everything is engulfed in a blue light. The End.

Then you get the second most interesting part of the game, the ending movie. First it shows Alyx hanging onto a pipe off a ledge, apparently about to fall. Next a vortigaunt is shown, carrying and setting down her lifeless body, while a vortigaunt voice-over says "This is more than anyone can bare, but we will perservere." Then it shows the new "mini-strider-like" enemies, vortigaunts fighting antlions, etc., while a Dr. Vance voice-over says "We're done running. This is our chance to take back our world. We're not going to lose it a second time." Cut to Half-Life 2: Episode 2 logo.

* The beginning, where Dog throws you into the citadel.
* Protecting yourself and Alyx when the elevator goes down, using the energy balls.
* Reinverting the core reminded me of the end of the original Half-Life 2. Not bad.
* At the end of the trainstation-level, when you get overwelmed by zombies.

the blue light at the end of "Exit 17", then it jumps straight to the credits, at which point the game simply exits, and restart.

Judging from the looks of the ending video I think Valve will try to show off their vegetation-rendering prowess, as much of this level appears to be set in the wilderness.

activating the elevator to the surface then being stormed by a mob of headcrabs and Zombines with 'nades. City 17's blowing up seemed surreal, but in a good way.