In a new video interview, Irrational Games' Ken Levine has outlined a few of the ways Valve's Half-Life games have influenced Bioshock Infinite. Specifically, Irrational's pairing of main character Booker DeWitt with supernatural damsel Elizabeth is a direct nod to the relationship between Gordon Freeman and Alyx Vance.
Elizabeth accompanies you throughout Infinite: Booker's initial objective in Columbia is to rescue her from the Songbird, a bio-mechanical jailor who's been watching over her from birth. "For us, the notion of having these characters [being the focus of] an FPS isn't something you think about all that often," Levine explained to Gamespot. "The best example is Alyx from Half-Life 2 because she's central to that story and she's an emotional driver in that story."
"I think what we're trying to do is take that notion and make a character who's even more central and has a relationship with a character who has a voice, unlike Gordon Freeman. And I think that we're making her more central to gameplay and making her more central to giving the player a voice in what he does in the game in terms of the tears."
The "tears" are gaps into neighbouring realities. Elizabeth can manipulate them, pulling material through to change the world around you. This ability will be used tactically - conjuring up an automobile to serve as cover - or in ways that pertain to the narrative. Famously, Elizabeth is shown attempting to resurrect a dead horse in one of the trailers.
Her innocence counterpoints Booker's cynicism. "It's just giving her a real story arc to go through," Levine went on. "This person starts completely naive, having never seen anything or done anything, but is thrown into this horrible world and forced to grow up very fast. How does it change her?
"Games are stories about change. She changes. Booker changes; and they change each other. She is really central, so we want to feature her a lot. But from a technology standpoint and a narrative standpoint, we're doing things that people really haven't done."
Much as the minds behind cult hit ICO invested considerable development resources into giving Yorda an independent personality, so Irrational has toiled to make Elizabeth seem like a real companion.
"We have this notion here that when you look at Liz and she sort of looks like a robot, staring at you creepily, we lose. We spent a ton of time and resources just figuring out what she does moment to moment. We have an actual actor. Well, an actor can make choices moment to moment. They can create content moment to moment because they're a person, right?
"With Elizabeth, we have to construct all of the underlying technology that generates what she does moment to moment; where she looks, how she crosses her arms. Like that shot we have where she looks at the camera--that's a shot that's actually generated. That's not an animation. That's a bunch of heuristics put together where she will occasionally look at the player.
"Depending on what else she's interested in the world, she might lose interest in something and then turn and look at the player. That's just a great shot we caught of her looking at Booker in the simulation."
I expressed fears that Elizabeth's eye-catching physique was a little at odds with her supposed sophisitication in a recent blog post. Levine's commentary is certainly food for thought. For more on Irrational's latest, check out our round-up of things you need to know about Bioshock Infinite. Here's the latest trailer.