I was planning on savoring the two episodes for Half Life 2, but ended up plowing through them pretty quickly. Which makes sense, both because they're shorter than the main game and because they share the same compelling design and sense of constant forward momentum. There's never a moment of RPG-ish free-roaming, where you can go wherever you want and tackle goals in your own order. Nope: you're always running from something, or racing to save someone, or fighting to stay alive one way or another. It'd be an exhausting way to live, but it's an exciting way to game.
I was really impressed with the episodes. In some ways, I like them even more than the main campaign of HL2. The biggest improvement is the cooperative AI gameplay. For most of the main campaign, you are totally on your own. You get to play with Antlion slaves for a while, which is entertaining, and towards the end you start leading squads of resistance fighters. I loved the idea of squad-based combat, but sadly the AI wasn't very sharp... they did great with a large number of low-level threats, like when you face a swarm of drones or a rival squad of Combine soldiers, but if, say, a sniper was pinning down an alleyway, and you told them to stay in shelter, then you crept carefully down the alleyway to take out the sniper, the squad would get bored and follow you, only to get popped one by one.
Here, for large chunks of the episodes, you fight alongside Alex. This is a Very Good Thing, for multiple reasons. First, she's gorgeous. I don't just mean visually appealing; the programmers have done a stunning job at modeling her movements. They're not only fluid, which is kind of the holy grail for character animation, but they're also unique and interesting. Way back in the main campaign, I remember being pleasantly stunned when watching her walk away, then pivot and continue walking backwards while talking to you. She's also a climber, regularly scrambling up ladders or rocks. When she gets into a car, she grabs the frame and then swings herself into the seat. Again, all this is done in-game in real time, not in some cut-scene. My hat is off.
Besides the enjoyment of watching your companion, though, it's a ton of fun from a gameplay perspective. There's a great section in one of the episodes where you're in a pitch-black underground tunnel. You need to use your flashlight to see anything. The flashlight can only stay on for about twenty seconds before it runs out of juice, at which time you need to turn it off and let it recharge, keeping you in the dark for seconds more. Eventually, you stumble across hordes of zombies. Alex is armed, but she doesn't have a flashlight. Therefore, you need to shine your light on the enemies for her to shoot them. They structure this brilliantly, forcing you to practice with the idea early on before you get a weapon, then leading you through fights where you could take the zombies out on your own but it's better (you save more ammo) if you let her do it, and finally a full-blown battle royale with dozens of hungry zombies coming at you in a seemingly endless wave while you're pinned down in front of an elevator.
Most of the enemies are the same as in HL2, with a few interesting additions. Some of the Combine soldiers have gotten infected by headcrabs, turning into a more dangerous form of zombie. These are a lot of fun: they're stronger and faster than the stock zombie, but in a great moment of comedy, they sometimes try to use a grenade on you. Only, they've forgotten how grenades work, so they'll hold it in their hand until it explodes. You'll want to keep your distance. We also get to see more stages in the Antlion lifecycle. Tiny, helpless grubs grow underground and are defenseless against your bullets and boots. Immature antlions can spit acid at you. Finally, there is a gigantic Antlion Guardian that's kind of like the queen bee of the colony. You only encounter one Guardian, and one is enough. Later, you run across Hunters, who may be the most difficult standard enemy: they can attack from great distances, do a lot of damage, move quickly, and have devastating close-range attacks. You also have a brief encounter with the terrifying creature that is glimpsed on the video screen near the end of HL2.
The storyline is really compelling. It actually starts out with a reversal of the HL2 ending: the G-Man is repelled from his attempt to collect you, and you and Alex are saved from the destruction of the Citadel by the efforts of your Vortigon allies. You learn that the Citadel's core is about to blow, and you don't have time to escape City 17 before it does. Therefore, you and Alex head back in to the Citadel to strengthen the containment field to give extra time for you and the remaining civilians to escape.
While in the Citadel, Alex intercepts a message from Dr. Judith, the reformed double-agent member of the Resistance. Judith is attacked and apparently killed on screen, while trying to transmit a set of coordinates. You also learn that the Combine is trying to send some sort of message through the portal swirling above the Citadel. It appears that they're trying to re-establish a link that would allow more reinforcements to cross over to Earth.
You secure the containment field and escape the Citadel. There's a hilarious segment where Dr. Kleinar appears on the Combine transmission screens, warning civilians to flee the city, advising them that the Combine suppression field has been shut down, and urging people to do their part and start procreating. You fight your way towards the train station, where you run into Barney, who is leading a rear guard of citizens. You provide cover for everyone to escape the city, then you and Alex take the last train out of City 17. You watch the Citadel explode, which seems to send shockwaves through the fabric of reality. The train crashes and Episode 1 ends in an epic cliffhanger.
Episode 2 sees you waking up in the wreckage of the train. You and Alex see that the Citadel has vanished, but the portal in the sky remains. (I have to say, the sight of the valley where the Citadel used to be is one of the most gorgeous scenes I've seen in any video game, including Oblivion.) Alex contacts White Forest, the resistance's base, where her father and Dr. Kleinar are. Also there is a new character, Dr. Magnesun, a pompous administrator from Black Mesa. When they learn about the transmission that Alex intercepted, they urge the importance of you immediately coming to White Forest. The transmission appears to be some sort of code used to establish the portal, and with that information, they should be able to shut the portal down and re-establish Earth's independence.
In a jaw-droppingly painful scene, Alex is stabbed through the back by a Hunter. (I initially mistook the Hunter for Dog. Whoops!) The Vortigons stabilize Alex's condition, but she is still critically wounded. You travel with a Vortigon into the Antlion colony to retrieve a substance that can save her life.
After a lot of effort, you eventually retrieve the substance. While the Vortigons are restoring Alex, time freezes, and you are revisited by the G-Man. He gives the longest exposition to date, both explaining more about his purpose and making himself seem even more mysterious. He instructs the unconscious Alex to deliver a message to her father: "Prepare for unforeseen consequences." You shift back to reality as Alex comes back to life. She seems weak, and for the rest of the episode, my heart would sink a little every time I saw her: bruised face, and two ugly-looking bloodstains on the back of her jacket where the Hunter stabbed her.
You resume your journey towards White Forest. Along the way, you have an incredibly creepy experience in the basement of an abandoned farmhouse: I forget the name of the creature you encounter, but I think it's called something like Ambassador or Agent. (Update: I just looked it up, they're called Advisors.) It looks a little bit like a giant, floating, cloth-wrapped grub. What's terrifying is that it takes control of you and all other humans, leaving you unable to move, although you can still look around. Its small, mechanical hands can hold a victim in place while a short sensory tentacle stabs into their throat and annihilates the brainstem. This one is weakened, and the two of you manage a fortunate escape.
You help out other Resistance fighters on your journey, reunite with Dog, and finally arrive in White Forest. Dr. Magnesun is as insufferable in person as on the video screen: he is obsessed with building his rocket, and believes that everyone else is incompetent and lazy. The other main characters suffer him more or less gracefully. You have a chat with Dr. Vance, who is disturbed by Alex's message: "Prepare for unforeseen consequences." Outside of Alex's hearing, he reveals that he knows the G-Man, and is conflicted about how the G-Man has saved his daughter only to use her as a pawn. You also get the feeling that Dr. Vance wouldn't mind having you for a son-in-law.
The three scientists review Judith's transmission. It proves to be the coordinates of a particular ship that makes them all very excited: it was developed by Aperture (hooray for the Portal reference!) and was believed lost forever. They are divided on what to do about it: Dr. Kleinar wants to use it as a weapon to help defeat the Combine, while Dr. Vance is emphatic that it is too dangerous, too much like the experiment at Black Mesa where everything went wrong, and should never be used. They table the discussion while Dr. Magnesun prepares the rocket for launch. Multiple attacks occur as launch time approaches. You manage to beat back each one.
One of those attacks was one of the most frustrating and difficult experiences I've had in any game. A seemingly endless wave of Striders, each guarded by Hunters, storms into the valley. This would be difficult enough if you fought them the standard way, with a rocket. Instead, the game has you use an entirely different method: use the gravity gun to grab a special sticky bomb, launch it up at the Strider, then detonate it with another weapon. If that's all that was involved, it would still be incredibly difficult. To make matters worse, the Hunters can destroy the bomb while you're holding it, or in mid-air, or once it's on the Hunter. And you can't stock up on the bombs: you can only grab one at a time, from a few specific locations on the map, which may be far from where your particular Strider is.
I swore a lot during this section, and eventually dropped down into Easy mode. Even in Easy, I probably used Quick Save and Quick Load more often in this segment than in the entire rest of Episode 2. It was not fun at all.
Still, once you're done with that, you're treated to some great, unbroken story. You have the honor of pressing the switch that launches the rocket. It gets off fine, and as everyone had hoped, the transmission it broadcasts closes the portal in the sky. There is much rejoicing: the Combine forces on Earth are now isolated, and the Resistance can start taking them down without worrying about an endless replenishment. With that major threat out of the way, Alex and you volunteer to go and rescue Judith. Dr. Vance repeats his warning that the ship she was tracking must be destroyed, not used. The episode is obviously winding down, and for a few minutes it looks like this might be the first-ever HalfLife game that doesn't end with a cliffhanger.
Until the Advisors show up. Two of them appear, seemingly out of nowhere, with no early-warning reality ripples. They incapacitate you, Alex, and Dr. Vance. The elder doctor is killed in front of Alex's screaming face; they sob out final words of love for each other. Alex begins crying out in terror as they advance on you. Suddenly, Dog bounds into the room and savagely attacks them. The spell is broken and you fall to the floor. The screen fades to black as you listen to Alex's sobs as she weeps over her dead father.
Man... the episodes were great! Terrific continuation of the story, and really fun gameplay as well. I said this in my original post, but what I like most about the HL series is its variety. None of the battles in the episodes felt exactly like the battles in HL2. There's always something different and interesting going on tactically. You need to think and adapt to survive.
The episodes also made me kind of wish that I had played the expansions for the original HL. I saw the boxes for Blue Shift and Opposing Forces, but never tried either one... I think I was in Linux-only mode when those came out. If those episodes were comparable to these, then I'm probably missing out on a lot of the HL universe's story. I wonder if these might explain more of the stuff that confuses me, like when and why the Vortigons joined the Resistance, or exactly how the Combine is related to the aliens from Xen that you battled in HL1.
I'm also very curious where things will go from here. I expect that we'll get another Episode... it feels like there are too many loose plot threads to carry over to a stand-alone HalfLife 3. I can imagine one final game that wraps up the storylines with Judith and the ship. Or maybe just takes you to the ship, where HalfLife 3 could start up. Eh... it's all speculation. I expect it will be good, though, whatever form it takes.