Half-Life 2: Episode 1 is a fun, if all too brief addition, to the series. However, it's a hard sell on its own.
Cons: Extremely short; Avoids really addressing the story too much; Doesn't do anything new
I don't know who Valve is trying to fool here. Half-Life 2 Episode 1 is an expansion pack. Sure it actually continues the official story, but it's still an expansion pack. Thus, without reading through the rest of this review, you likely already know whether or not this game is a good buy.
For the more persistent of you, I'll have you know that Half-Life 2: Episode 1 stands toe to toe with its predecessor. In fact, I suppose that in a way it's better paced than the original #2 because it has no downtime. From start to finish, you are going to be engaged, and the final scene in the episode is one of the best in the series to date.
Here's the catch: the game can be finished in under 5 hours. And, perhaps because of the lack of time given, the story kind of suffers. The basic idea for this game is that you and Alyx Vance need to escape from City 17 for reasons that are obvious to anyone who finished Half-Life 2 (trying not to spoil them though). What's disappointing, however, is that that basic idea forms almost the entirety of the story. This episode is clearly part of something bigger, and chooses to move the plot along rather than make any major additions on its own.
However, the less than 5 hours you spend with the game are pure fun. You are constantly working alongside Alyx Vance, which adds a bit to the game as her character is fleshed out ever so subtly and you never get the feeling of chronic loneliness present in past entries in the series. The game tends to spend a bit more time in the horror shooter realm than Half-Life 2 did, but seeing as those portions of Half-Life 2 were among the most memorable, this isn't a major complaint. All in all, it's an enjoyable ride, if it feels perhaps too similar to Half-Life 2.
But that's not necessarily a bad thing, considering the strong base, and the presentation aspects hold up just as well. The graphics engine continues to show its strength, and the voice acting, facial animations, etc. are still among the best in the business. However, this comes with the added minor quirk of being sparse in the usage of music; something that felt just as weird in Half-Life 2 as it does now. Again, it's not a major point that shifted my opinion, but I think it could've been applied to enhance the effect.
At this point, it feels like this is just a short redundant review of Half-Life 2. Which is really fitting, given that Half-Life 2 Episode 1 is a short redundant version of Half-Life 2. This makes the game, while enjoyable, a bit hard to recommend, although a $10 price certainly helps sweeten the deal for those who can't get enough of Gordon Freeman's adventures. However, I can still recommend you play this game.
Just get it as part of the Orange Box and get a better bang for your buck.