Half-Life 2: Episode One Hands-On - New Battles, New Opponents, and the Flight from City 17

Eighteen months is a long time to wait for answers, but fans of Valve's acclaimed Half-Life series are used to long waits. Still, the cliff-hanger ending of 2004's best-selling first-person shooter Half-Life 2 left a ton more questions than answers. The good news is that with the release of Half-Life 2: Episode One later this week, Valve is prepared to reveal some of those answers. We know because we recently had the chance to play Episode One to get an idea of what to expect, as well as find out what answers Valve is going to reveal. PLEASE NOTE: While we won't spoil the major plot points in this preview, we will reveal some details about how the episode plays out.

First, you might be wondering what the deal is with this entire episodes thing. Basically, Valve has decided to develop episodic content rather than a full sequel. The reasoning for this is that it lets the company get new content out more quickly to its fans, as well as create content that's more tailored to what worked and what didn't work based on fan feedback. Episode One is the first of three planned episodes that continue the Half-Life story, with the second episode due out around the end of the year and the third episode scheduled for next summer.

As fans know, Half-Life 2 ended with an explosion taking place mere yards away from Gordon Freeman, the hero of the series, and Alyx Vance, Gordon's companion and intrepid love interest. Needless to say, how they survive the explosion is quickly resolved at the beginning of the episode. More importantly, new plot points are also introduced. The G-Man, the mysterious puppet master that manipulates Gordon, is no longer in the picture, and now Gordon is basically a free agent. The bad news is that they're still in the ruins of the Citadel, and the Citadel reactor is out of control. The bulk of Episode One deals with the flight from the Citadel, as well as the race to flee City 17 before the Citadel reactor overloads and explodes.

Episode One feels quite different from Half-Life 2, or even the original Half-Life. That's due to the fact that you go through the entire expansion with Alyx by your side, and the artificial intelligence is good enough to make it feel like you're playing alongside a human player at times. The team dynamic that results with this is an interesting change of pace from Half-Life's traditional lone-wolf gameplay, as you often have to rely on her to give you cover while you tackle the many different types of tactical and environmental puzzles throughout the game. In one situation, you may find yourself in a pitch-black environment, and you have to use your flashlight to illuminate enemies for Alyx to target. In another, you'll find yourself being overwhelmed by swarms of ant lions, and you have to figure out how to get out of the death trap.

Spending so much time with Alyx also has the benefit of helping to flesh out the story better. Not only do you have someone to provide a running commentary of what's going on, but you also grow more attached to Alyx and her sense of humor. Don't worry about missing out on other old friends, though, because all the major characters from Half-Life 2 make an appearance, including one or two that you don't expect. The original top-notch voice cast is back, and the script provides even more character warmth and humor than before. (Dr. Kleiner's cameo is a particular hoot.) Meanwhile, if you were hoping that Gordon Freeman would get a voice, forget about it. As ever, since the entire episode takes place from Freeman's perspective, and since you play the game in Freeman's shoes, providing a voice would ruin the immersion of the game.

Surprisingly, the Half-Life 2 arsenal remains pretty much unchanged. You'll rely on the versatile gravity gun for the opening levels (it loses the supercharge it gained at the end of Half-Life 2), but eventually you'll recover your familiar collection of guns and grenades, from the pulse rifle to the iconic crowbar. You'll need them to battle the familiar army of Combine troopers, zombies, and other opponents that you saw in Half-Life 2. There are some new additions, though, such as zombines, Combine forces who have been converted to zombies thanks to head crabs. These guys are a lot tougher than traditional zombies, and they have a nasty habit of making a suicide charge at you with a live grenade in their hands. Have fun.

Valve has said that Episode One packs about four to six hours of gameplay, and that sounds about right from our gameplay experience. Veteran first-person shooter fans will definitely have an easier time than casual action gamers, especially with some of the puzzles, which rely on you to quickly evaluate everything in the environment and figure out what you can manipulate with the gravity gun to make your job easier. As with Half-Life 2, there are three difficulty settings in the game, and you can switch the difficulty in midgame, so if you encounter a difficult patch, you can make the game easier, or if you're bulldozing through the game, you can tweak it to be a bit tougher.

On a technical note, Episode One incorporates high-dynamic range lighting, the lighting technology that makes light seem warmer and more lifelike. That's another advantage of episodic content, according to Valve, since the company can gradually introduce new technologies in each episode. Episode One also does another interesting thing with lighting, something called hero lighting. Basically, in Half-Life 2, everything was lit by the same source. However, to emphasize the heroic nature of Alyx in Episode One, she's basically illuminated in a bank of lights that make her stand out even more. It's an incredibly subtle effect, but it works.

It goes without saying that while Episode One provides some long-awaited answers, it also raises a bunch of new questions. The flight from City 17 is but the beginning of this new episodic storyline. Though Dr. Breen was defeated in Half-Life 2, the alien Combine remain and are planning something devastating. You can't help but get the feeling that events are beginning to build toward some awesome climax further down the road. When you finish Episode One, you'll see a trailer for Episode Two that will whet your appetite by providing glimpses of what's to come. The good news is that instead of 18 months, we'll only have to wait six months before the next answers are revealed. Half-Life 2: Episode One will launch on June 1.