If adventure game developers play just one game this year, I hope it's Mass Effect. Why? Because this RPG/shooter introduced a dialog system that is so fluid and natural that it should make every adventure game blush with envy.

Mass Effect has brought the biggest advancement in game dialog in probably a decade. Sure enough, EA (the largest game publisher) has even decided to spread this new dialog system amongst all of its development teams. Its innovations are very subtle, however. On the surface the system seems no different from anything you've seen before, but there's several small but profound differences.

Real conversations have a natural rhythm to them that is unfortunately lost in games. Each time the player has to pick a response there's an unnatural silence, with the other character staring blankly at you as if frozen in time. Not so in Mass Effect. It allows you to select a response very quickly and easily, eliminating most of these gaps in conversation. Below is a video of a typical dialog sequence in the game.

As you can see, there are a couple of small but crucial differences with other dialog systems.

1. Dialog options show up on screen even before the other character is finished talking.
In real conversation you usually already know what you're going to say before you're going to say it. Allowing players to be one step ahead makes conversations more fluid. It also makes them more dynamic, as you can listen and think ahead at the same time.

2. Dialog options are very easy to read
Very short (3-5 word) sentences represent the essence of what the protagonist will say when the option is chosen. These short staccato-style sentences are many times easier to interpret than icons and much faster to process than complete sentences.

3. Certain responses always show up in the same place
Different slots on the dialog wheel roughly correspond with the different approaches you can take during a conversation, such as aggression, bribery or diplomacy. (This is a bit like the old Tex Murphy games.) For instance, after a while you'll intuitively know that a certain slot always has the most aggressive response assigned to it. After a while, you can carry out conversations this way even without reading all the options.

As a result some of the better conversations in Mass Effect feel more like a conversational sparring match, or even some kind of mini-game. There's a true feeling of action-and-reaction and immediacy. The highly cinematic presentation makes for some great icing on the cake, with camera cross-cuts, close-ups, pans, facial movements and even physical interaction between characters.

The dialog wheel interface was specifically developed for the analog stick on an Xbox 360 controller, so I wouldn't actually suggest that other games blindly plagiarize it. But Mass Effect does clearly demonstrate that developers should not stop experimenting with new dialog systems.

The adventure genre has already seen countless subtle variations in the way conversations are carried out: branching dialog trees, topic icons, notebooks, text parsers, topics-as-inventory-objects, dialog with time pressure (think Fahrenheit), and the list goes on. Yet none of them have ever truly felt quite right to me. I believe Mass Effect points the way towards fixing the small nagging issues that have persisted in game dialog for so long.