NWN2: Mask of the Betrayer - Preview @ GameZone

Mask of the Betrayer introduces Red Wizards as a prestige class and a new race called the Genasi, a group of half-breeds incorporating earth, air, water, or fire elements. Players will be able to begin the game by bringing over a previous character, by starting a new character from scratch, or by using a pre-loaded character.

[…] The night and day cycle was an interesting feature of the original that didn’t have a major affect on the gameplay. That changes with Mask of the Betrayer, as you now have the chance to access a special portal at night.

After entering the portal, players will end up in a darker, more vicious world. The color array changes to an artistic black and white – certain hues shine through, but the general look is darker and filled with stark contrasts.