Great sequel to a great game.
The major change that everybody will see shortly after starting the game is that the D&D ruleset has been upgraded from AD&D 2nd edition to D&D 3rd edition. At first I wasn't quite content about it. It takes some time to get use to it, but when that happens you don't want to go back to previous edition.
The story is once again saving the world from great evil - this time, as it first seems, goblin hordes - but after revealing some more plot elements the whole story becomes a little more complex and interesting. Still far away from the greatness of "Baldur's Gate 2" but nevermind that ;) There are many characters and places from "Icewind Dale" which is a very nice thing for loyal fans of the series.
Graphics is slightly better than in the mentioned "BG2" with 800x600 as a default screen resolution (however 1024x768 is a lot better) and everything generally improved in comparison to first "IWD" including backgrounds, animations and spell effects. Also HUD got greatly improved which is now placed only at the bottom of the screen instead of around it. All the buttons are very well placed and every bit of space is used very good. Due to this finally in an Infinity game you can see quite a wide view of a terrain.
Sound is a mixture of old stuff from "IWD" and some new sounds and of course new voices (there are also voices from "Heart of Winter"). Music consists of epic symphonic tracks and similar things just like in the first part. It's hard to say if it's better or not, I'd say it's just as good as in previous game.
From the new things, there are new classes and races (and sub-races) so you probably would like to create a new team from scratch instead of importing your team from "IWD" which is naturally easily doable. Game is of course loaded with dozens if not hundreds new items, new enemies and redesigned spells - oh, how much I love horrid wilting :D
Not going into more details the game is awesome and if you played the first part or BioWare's "Baldur's Gate" games you know what to expect and that is a great, great RPG with solid story, complex character development and outstanding combat - even if the final boss is unfortunately only just a little bit harder than in "Shadows of Amn" while I was expecting something more challenging. It's definitely worth playing for both hardcore players and just RPG fans.