The major addition to the single-player game is, however, the new party system. As you play, you’ll bump across other adventurers on the road, in taverns, and so on. With a little persuasion, you can then get them to join you in your quest, and your party can grow as large as four members. What’s more (unlike the original) you can directly control any member of the party at any time, while also being able to pause the game and give general orders to members you aren’t directly controlling. Interestingly, Obsidian has also incorporated an influence system, in which your actions dictate your ability to get your party members to do what you'd like them to do.
Another addition is the dialog system, which offers a more natural and cinematic presentation. Granted, conversations still function almost exactly the same, but everything looks (and sounds) much more exciting while it happens.
But really, the enduring strength of the original NWN wasn’t its single-player game, but in the toolset that enabled users to create their own dungeon crawls, and naturally, that’s also a major feature of NWN2. The new toolset comes with a completely user-editable interface, with windows that can be moved, tabbed, and pinned anywhere you like. Interiors are no longer bound to a single decorative theme, so you can mix and match styles. Also, there are now “unfurnished” tiles that can be customized just about any way you’d like. Exteriors now use height adjustments for a much more natural-looking terrain, and there are new tools for generating trees and scrub, so you won’t have to place every single bloody tree by hand (ahem).