Episode One defines "short but sweet," totally refining the Half-Life 2 experience in four near-perfect hours.
Episode One's story takes the player out of City 17, as directly opposed to the original game, and it's fitting that such a story retreads a good deal of HL2's territory while approaching things in a refreshing way. There's only one new-looking area in the game, and it's nothing more than a novel view of a place the player's been to before, but that's really not the point. What happens in those places is the meat of the game, and it's far more exciting and varied than in Half-Life 2. Puzzles, for instance, felt poorly distributed in HL2. They would generally be fairly large, but they would pop up only at certain points, rather than being smoothly spread across the game. Episode One corrects this, due in part to the fact that the environments you're passing through are now much more unstable and ruined. This allows for dozens of simple puzzles and timing exercises, making the experience feel more fluid. The combat also feels great this time around, and the new Zombine actually helps a lot. It's the most unpredictable and fearsome foot soldier in the game, and its punishing attacks bring a sense of urgency to the formerly middling zombie battles. There are also quite a few rocket crates, oddly enough, and the ability to dole out explosive damage almost at will is quite liberating in the sequences where it is possible. The best addition, though, is the new focus on fighting through enemy-versus-enemy battles, especially since the foes involved are so related to one another. It's very interesting to see Zombines tearing through their former squadmates, overpowering Combine troops with their fierce melee attacks. Though Episode One may not feel like a whole new game, it gets everything wrong with HL2 exactly right.
The presentation of Episode One is, surprisingly, another marked improvement. There was very little fault in Half-Life 2's graphics for instance, but the artistry of the lighting has been greatly upgraded. The Source engine's fixed-light-source model is still disappointing, but Valve's HDR usage is very well done, and the pitch-black middle chapter is highly atmospheric and an ideal showcase for the flashlight effects. The cinematic aspects of Episode One, too, are similar but enhanced. I won't spoil all the details, but one particular interaction with Dog near the start of the game is flat-out inspiring, and many events with that level of flair and style show up all over the game. The biggest leap forward, however, is in the music. The score seems more energetic and rock-influenced, and the grating techno players were subjected to in Half-Life 2 is gone. Voice and sound work, as always, is basically perfect, and so the renovations to the musical aspects of Episode One make its aural experience unmatched.
But, as I'm sure every reviewer will say, it's short. It took me four hours to beat, and I consider myself a fairly methodical player. The end is beyond abrupt, too, though less cheap-feeling than that of Half-Life 2. Still, one must consider what they're paying for this. This game, which pre-sold over Steam for only eighteen dollars, is a concentrated game with a level of polish most developers only dream of. The hours-per-dollar ratio is actually pretty good, considering how great each hour is. I myself was no great fan of Half-Life 2, but after playing Episode One, I can't see myself passing up the next two installments. If you can bear the short length, get this game now.