Half Life 2's Developer Commentary

Over Labor Day weekend, I got around to finishing Half Life 2: Episode One, the deeply satisfying expansion pack that picks up the storyline of Gordon Freeman as he tries to escape from City 17.

As great as the game was, I was blown away by the in-game Developer Commentary system. Each bit of audio is a “commentary node,” a little floating speech icon that can be activated by aiming at it and hitting the “use” button. The dialogue then plays, with additional information about who’s speaking and the length of the clip. (See videos below.)

Most of the game’s 115 nodes are audio only, pointing out interesting tidbits about the scene you’re currently in, such as the visual design, character dialogue, or gameplay. Some of the best examples discuss the iterations a stage or puzzle went through, why original versions didn’t live up to expectations, and how they reached their final design. It’s a fascinating glimpse into the minds of the developers, very much like sitting next to them as you play through at your own pace.

But a few commentary nodes do much more, taking over the player’s view to show them something hidden or entirely new. I’ve captured video from some of my favorites.

Here, in the Citadel’s Core control room, you can see three separate commentary nodes. The first two were from earlier in the game, referring to the first time I was in this room. The third node — my favorite of the game — whisks you away to an entirely hidden part of the map to explain how real-time TV displays are made. Note how the color of the third icon changes after it’s activated, marking itself like unread-to-read mail.

In this turret scene, the first commentary node explains Alyx’s behavior and how the turret design was modified after playtesters complained. The second turns on a hidden “node graph” layer and discusses how designers can use it to improve NPC’s movement and combat. Note that the player is invulnerable to damage for the duration of each clip, so as not to distract from gameplay.

This final video explains Alyx’s dynamic fighting animations by taking over the player’s perspective and cloning multiple copies of Alyx and a zombie, which creates a Mortal Kombat-style walkthrough of several variations. Fun!

There have been a couple earlier attempts at in-game commentary, most notably the “Developer’s Cut” of The Chronicles of Riddick: Escape from Butcher Bay (2004), a game that sounds awful but is widely considered one of the best modern first-person shooters. Valve was clearly inspired by Riddick, but has refined and improved the idea, making it so vital and interesting that it easily added four hours of replay value to my $20 purchase.

Sadly, according to Valve’s game statistics, only 15% of players have ever turned it on. So, try it out and help raise that number (it’s buried in the audio options). I really hope this feature becomes more popular in new games, or even as special edition reissues for older games. Hearing the original developers discuss, in context, games like Ico, Deus Ex, or (gasp!) Day of the Tentacle would be a dream.

Also, if you’ve finished HL2:EP1, this 47-minute fan-made commentary is thoughtful and funny. Highly recommended.


    I, too, completed HL2:Ep1 over the Labor Day weekend and was a little sad to see it end. Thanks for the reminder to play through one more time with the developer commentary on — something I had completely forgotten about.

    I hope this feature makes its way to the XBOX 360 version. Since my PC is dead and there isn’t a Mac port the XBOX is my only way to HL2.

    Excellent idea, and seems to be very well thought out. I wish it muted the game noise a bit more, as sometimes the character dialog and explosions made it hard to make out the commentary.

    Normally, I don’t go running into combat while listening to the commentaries… I usually sit quietly and listen, but I think I felt obliged to do something interesting while capturing the video. 🙂

    Yeah, this is a nifty little feature. HL2, however, is not the first to implement it. The little-played and much ignored Chronicles of Riddick: Escape from Butcher Bay had this feature, once the game was finished.

    Whoops, completely missed the text underneath the embedded vids. I remember when Valve released the Lost Coast map, also with embedded developer’s audio commentary. Mostly they explained the HDR procedure, and why and how it looks the way it does.

    All in all, I think it’s a feature that most (if not all) medium- to large-budget games should implement from now on. Like you say, it does nothing but add value to what may otherwise be a disappointing (or over-priced) game.

    The commentary bubbles really are an excellent replay incentive for the game. Valve first used them in their playable Lost Coast tech demo to explain the new HDR effects and other Source engine upgrades.

    Coincidentally, I was also playing through Episode One over the weekend, and I just realized, from comparing your clip of Alex fighting the zombies to my gameplay sequence, that Valve did not script which animations would play during the commentary. True to form, the animations demonstrated during the commentary clip must be selected based on random placements of Alex and the zombie. Cool!

    Neat bonus for the players. I myself am waiting for the “second episode” to come out until I play the first one. That way I can enjoy the H-L universe twice as long (sort-of) and also won’t have to buy a new graphics card just yet (my old one died a couple of months after I played H-L2 and I now only live on a GeForce4 Ti 4400).

    I wonder if it’s possible to find where the Combine are “broadcasting” from in some of the other videos. I always assumed they were pre-rendered. Someone could make a pretty interesting guide by documenting all of these locations.

    It is! We should try and make a campaign: The more people ask Lucasarts for another game, the faster it might appear. I have already sent them an email some weeks ago, but without any response 🙁

    I had NO idea the commentary even existed! I’m going to replay HL2 (i miss it anyway) and check it out.

    BTW, I wish that had left the even turret knock-over “bug” in; those things were a bitch!

    I think the commentary is awsome, i want to see it in the other hl games and in the new games because it gives an idea of how the game was made, and how much time went into making it and perfecting it.

    The commentary being woven into the game so that you can hear them while you re-play the game is a good idea; but Valve also should have also let you listen them by themselves if you don’t want to re-play the whole game to just to hear them.

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