Never mind the game's rave reviews, the beginning of the first-person shooter "Half-Life 2: Episode One" is a problem. That's not what the reviewers wrote. That's what the game's developers say -- and they say it in the game.

The confession is right there in the code, represented as a floating word balloon hovering in the game's opening area, visible to any player giving the game a go with the audio-commentary feature turned on. When clicked, the speech balloon spins and an audio clip plays. One of the game's developers at Valve apologizes for a design choice that has the player discovering that their own character can't make a simple jump that a computer-controlled ally can. It was necessary for the flow of the game, the developer explains, adding, "honestly, we're not especially happy with this crutch."

Released in June, "Half-Life 2: Episode One" includes the option to reveal more than 100 floating speech balloons of audio commentary explaining the whys and hows of some of the game's smallest but most significant details. Players can play the game without ever seeing the balloons or listening to the clips, but if they choose to activate them, they can hear developers chatter away as they blast away the forces plaguing City 17.

Non-gamers might find this completely unremarkable. DVD movies have included commentary since they had shrink wrap. But "Half-Life" joins only a small handful of games released in the last decade that include any commentary tracks at all, one of gaming's most revealing features. (Did you know "Grand Theft Auto" and the war against the Taliban inspired a major "Star Wars" game?) So why are a few proud developers doing it, and what's been keeping everyone else from jumping onboard?

"Over the years we've brought in hundreds of play testers to sit down and play our games while we all watch and take notes," Valve project manager Erik Johnson told MTV News. "What we found was that all of them were interested in why we made the choices we made, and how they had evolved over the course of the game's development. In a lot of ways, this is the kind of conversation we're trying to replicate with the commentary system."

So, yes, players, that is an enhanced refraction shader being used in the opening segment of "Half-Life 2." The commentary says so. And, perhaps more interestingly, player-hero Gordon Freeman's cute female companion Alyx follows rather than leads, because when she used to lead, test players found her annoying. And the pod in the heart of the citadel will play a big role in "Episode Two."

Valve's Web site reports that 15 percent of the people who have played "Episode One" since its June release have activated the game's commentary feature, just under half the number of people who have finished the game. That's enough for Valve. "There isn't really any chance of us leaving it out in our future titles," Johnson said.

The earliest audio commentary in video games may very well be the one in Factor 5's 2000 "Star Wars" starfighter-combat game "Battle for Naboo." Back then, games were on CDs and cartridges, neither of which left a whole lot of room for bonus audio tracks. Factor 5 managed to squeeze a few minutes of commentary for each of the game's levels onto their game's Nintendo 64 cartridge. Factor 5 president Julian Eggebrecht could not be reached to explain how and why -- nor to say whether the company's next title, the PS3 dragon-combat game "Lair" will be their fourth-straight game with an unlockable commentary track. But the developers' previous efforts make them not just the most prolific commentary-makers in the industry, but also the best advertisement for why they're worthwhile. Where else can gamers listen to developers talking comfortably about their games without the distraction of pesky reporters and without the need to talk in sales-pitch sound bites?

Consider the audio track in Factor 5's "Rogue Leader II: Rebel Strike," a 2003 "Star Wars" game for the GameCube. Eggebrecht and colleagues reveal that their choice to shake up their franchise and let players leave their fighters and run around on foot is in part due to the success of "Grand Theft Auto III." They discuss the relevance of PlayStation staple "Devil May Cry" to their own game, and call out the second "DMC" game for not being as good as the first. They lament frustration over scuttled plans to tease their game at an earlier E3, explain how one level of the game was inspired by, of all things, CNN footage of Afghanistan, and examine the different art styles of "Star Wars," "Star Trek" and "2001." Of "Star Wars," artist Paul Topolos says, "There was some cheese there." Developers don't often get this frank -- not on the record.

What will it take to get more game makers to spill like this? The most significant obstacle is time. Movie directors have the luxury of recording commentary for DVDs that arrive months after their film is completed and released in theaters. Game makers, if they want to include commentary with their title, need to record it in the 11th hour of a game's development, right at crunch time. Insomniac Games has included a behind-the-scenes interactive "museum" in two of the company's four "Ratchet and Clank" games, but has never provided an audio commentary. Company president Ted Price told MTV News that he's wanted to since the first "Ratchet" game, but never thought they'd have the space on their game disc and never planned early enough to record it. "Ironically our conversation now is providing the impetus for me to go back to our guys for our next title and say, 'Let's start working on it right now,' " he said. (Insomniac fans, he's talking about the game after "Resistance.")

One way developers could get around the timing problem would be to offer commentary as an after-release download, the kind of so-called micro-transaction that publishers currently reserve for bonus cars and multiplayer maps that, for a few dollars, can be tacked onto a game a few weeks after a game is released.

Valve's Johnson said such a method is unnecessary for the "Half-Life" team because they have a system that works: During development, everyone on the team suggests where speech balloons could go, a smaller group picks them and they're recorded. The whole process is done in a week.

Some of the commentary nodes in "Episode One" show off the unique abilities of gaming technology. Activating one balloon whips the camera around to focus on the action being described. Another balloon cues up certain animations that are being discussed. Johnson said Valve is hoping to improve the commentary system for next year's "Episode Two" with a feature that allows players to view multiple iterations of an in-game object or character as commentary plays, so gamers can see how things literally changed shape during the course of development. They're also hoping to support their commentary system in multiplayer matches of "Episode Two" companion product "Team Fortress 2."

If enough players show interest and if the technology is there to make commentaries, more can be expected in games. But Insomniac's Price cautioned that one other hurdle needs to be cleared: Developers need to realize that they've got a reason to talk. "Many of us have always considered [ourselves] on the fringe of mainstream entertainment. ... Until you have somebody from the outside knocking on your door saying, 'Hey guys, open up. We're really interested in how you guys do this stuff,' it's hard to take the next step." So if gamers want audio commentary, they have to let it be known.

Hey developers -- it's OK to open up.