Interview: Half-life 2's David Speyrer

That seems like quite an achievement. Companions tend to be infuriating. How did you avoid this with Alyx?

DS: Alyx doesn’t generally dictate the pace of your forward progress through the game. When she does that, it feels like she’s playing the game and you’re the tag-along. We learned this in Episode One, and applied it in Ep Two as well. The player should dictate the pace of moving through the game.

And we’re very careful that it’s the player who solves most of the problems. Alyx can state a problem- “We should really figure out a way across this bridge”- but it’s important the player should be the solution. It’s not much fun watching an NPC play a game for you. We deliberately keep the player as the prime mover, and Alyx’s job is really to augment the gameplay, create interesting gameplay scenarios, and reward you for a job well done. There’s a whole set of rules- the player dictating the pace and Alyx not stealing the fun- that we make sure we follow. It was a lot of work achieving the Alyx you see in the game today. It took a lot of iterations, and even all of her responses to the events which happen in the game took a lot of fine tuning. She can’t talk too much, and she can’t be too quiet either. There’s a middle ground where she’s talking enough to show awareness of what’s going on around her. We try to make everything she says interesting or entertaining, so we really pay attention to how people respond.