Sleeping Dogs has been highly praised for its voice acting, sure it might be a little confusing on the story-line front, but I don't think I've ever played another game where the characters sound so... real.
Obviously, with any video game involving dialogue and characters, there's always going to be some form of script. What developers try to achieve however, is to make sure that the game doesn't feel scripted. Few games achieve it. With sports games like FIFA, in the past the commentators haven't even used scripts, they have just made words up along the way giving the game a more realistic and dynamic feel. With sports games, it's easier to achieve. So how have United Front Games managed to do this with Sleeping Dogs? It's difficult to explain - you need to hear it to believe it, but it sound as if UFG have just got a few voice actors, given them a script, but a script that doesn't have strict rules, rather, a script that just talks about a topic, this then gives the actors something to go on, and from there they can talk about whatever they want, how they want. It just feels a lot more natural. On one mission you have to get this girl all the necessities for her upcoming wedding, and chatting to her in the car literally sounds like you're chatting in a car for real. You wouldn't tell that they were in a recording room if you didn't know.
That's why other games need to look at Sleeping Dogs and take note. When done well, voice-acting can be a game changer.