The Game Engine
System Shock 2 uses a enhanced version of the same engine that went into Looking Glass' other masterpiece Thief: The Dark Project . This means three good things: excellent artificial intelligence, awesome sound, very good physics, and one bad: no eye candy.
The AI is an enhanced version of the AI used in Thief, so you can expect the bad-guys to be just as smart, if not smarter! Enemies will be sensitive to light and sound, which means that not only can they hear you, but you can hide in the shadows.
The sound in System Shock 2 will be every bit as good as in Thief (its the same engine!), which some publications deemed to have the best sound system in any game ever made. Sound will be realistically modeled in the 3D world, and takes advantage of the latest EAX & 3D positional audio technology. Players can tell where an enemy is based on where the sound is coming from, and also from the type of sound, since all floor-types make a different foot-fall noise. You can also tell the type of enemy, since all enemies sound different, and the enemies awareness of the player, since it will broadcast this as it either stands idly, searches for you, or attacks you. Of course, the converse of this is all true as well.
The physics modeling is of course all state of the art, giving all objects mass and volume. Thrown objects will arc in flight, loose objects will be thrust away by the blast of an explosion, heavy objects will sink in water and light ones will float, and so on and so forth.
The engine in SS2 will feature significant visual enhancements over the Dark Engine. A 3D accelerator is required, and acceleration will be supported through Direct3D. 3D NOW! will also be supported. System Shock 2 supports the usual: Colored lighting, light-mapping shadows, 16-bit graphics. S.S.2 will probably not support VR peripherals such as HMD's head tracking and stereoscopic 3d gear or gloves. Smoke is in the game in the form of a particle system, but fog is not. Though the game is by all means very good-looking, some would argue that it is not up to the standards set by Unreal or Quake 3.
Music will play an important role in the mood-setting. Rather then a random looping midi or mp3, or red-book audio, music will be handled on a per-situation basis. People who have played Thief, Half-Life or Descent 3 will know how this works. The music will be more music-like then Thief, more frequent then Half-Life, and less annoying (hopefully) then in Descent 3.
The enemies in SS2 will be polygonal & motion captured.
It is unknown if the level editor (Dromed) will be released to the public yet. However, it has already been released for Thief.