Neverwinter Nights can be played in either single player or multiplayer mode. Single player is somewhat like what a one-character Baldur's Gate would be. You do not have a party, though you can hire AI henchmen. You do not need a DM, as the modules will be able to run by themselves without supervision. All play is done through a 3D, isometric 3rd-person point of view. The camera is semi-autonomous in that it adjusts itself to suit the situation, but you can fine-tune zoom levels if you wish.
Of course, the big draw with Neverwinter Nights is the multiplayer aspect. NWN's main purpose is to simulate the pencil and paper role-playing experience on the computer. As such, there should be a Dungeon Master and several players. The DM uses a special version of the client that gives him many powers, such as the ability to possess monsters and NPCs, to drop items, and in general to modify the game as he pleases.
Players work together as a party to defeat the challenges placed in their path by the DM. Most of these challenges should be planned far in advance, and implemented in the module, otherwise the DM will be overwhelmed with the workload. A well-designed module allows the Dungeon Master to simply observe and adjust, or even take over an event that is running.
The Quest for Spell Checking
"Evil DM Grin" not included
To give the NWN Dungeon Master as close to as much power as they get with a pencil and paper game, DMs will have the Solstice Toolset. Since Neverwinter is a real-time game using a system designed for turn-based play, some adjustments had to be made. BioWare has created some dirty tricks for DMs to use.
For example, they have a dynamic difficulty slider - if players are in combat and are having an easy time, just turn difficulty up a notch and they'll suddenly be sweating a little harder. Such touches are just the tip of the iceberg involved in giving the DM the power he needs. To make other tasks easier, you can customize the interface to filter chat levels, to make a bigger chat window or a smaller one - whatever suits your fancy.
But how does the toolset itself work? Well, you start by creating a map. The maps are made of 10x10 meter tiles, and each map can have a 32x32 grid of tiles, though smaller numbers work quite fine. Maps are created like they would be in StarCraft - pick a tileset, the computer randomly generates some terrain and you work on the details.
You can add water, raise and lower terrain and even drop "features" here and there. Features work like Doodads did in SC - cosmetic touches thrown on the tiles to help give some variety, but only you can place these features - the computer never uses them during random generation.
Weapon, item and character/critter creation are also controlled by the toolset. When creating weapons and items, after you are done with the basic looks, you then go on to edit abilities. You can make items magical with damage and "to hit" bonuses or even special bonuses against certain classes of monsters. If you create a +5 weapons, the +5 damage bonus can also be a specific kind of damage, like acid, fire, electricity, and so on. Then there are also "tack-on" abilities, like doing an extra 2D4 of electrical damage in addition to the +5 acidic. Once you are done defining an item's abilities, you can name it and even give it a description or history!
After you place critters or characters on the ground, you can script them with various behaviors. Many scripts will be included with the editor, but you can also make your own if you choose. Trent described the scripting power as greater than even Baldur's Gate II, which is rather impressive considering how much leeway designers had with the BG2 scripting system. The scripting language cannot, however, be used to alter the base 3rd Edition rules, nor will there be a mod pack released.