Following its predecessor, the game takes place in the Forgotten Realms, a fantasy campaign setting, and is based on the Advanced Dungeons & Dragons 2nd edition rules.

Opening shortly after the events of Baldur's Gate, the game continues the story of the protagonist, Gorion's Ward, whose unique heritage has now drawn the attention of Jon Irenicus, a powerful and sinister mage.

Shadows of Amn received critical acclaim, being praised for its gameplay, artwork, and voice acting, and is often regarded as one of the best video games ever made.

The game begins with character creation[4] through a series of configuration screens,[5] choosing such things as class, ability scores, appearance, and alignment.

[3][7] Once in the game world, the player may recruit certain non-player characters (NPCs) to travel with him or her, though only five may do so at a time; depending on who is present in the group, bickering, romance, and side quests can result.

[29] During character creation the player chooses a class:[30] fighter, ranger, paladin, thief, bard, mage, cleric, druid, barbarian, monk, or sorcerer (the last three of which are new for the game).

[41][43] The Shadow Thieves, the Cowled Wizards, and the Harpers, a semi-secret conglomeration of good organizations,[38] all factor prominently into the story and provide side quests.

[22] Besides Athkatla, other places the player will pass through include: an island, on which stands both the port town of Brynnlaw and the asylum Spellhold; the Underdark;[3] the city of Suldanessellar; and the Astral Plane.

[3] There are also other places, which may be explored: the Umar Hills,[3] where people have been disappearing; a temple ruins,[3] fallen under the shadow of the Shade Lord; the de'Arnise Keep, home of the de'Arnises but recently overrun by trolls; the town of Trademeet, under attack by animals; a druid grove connected to Trademeet's woes; the Windspear Hills, where the player becomes entangled in the intrigues of Firkraag, a dragon; the underwater Sahuagin city; and the Planar Prison.

[48][47] The story of the first Baldur's Gate followed their adventure along the Sword Coast, where the hero learned of their heritage and defeated their half-brother Sarevok, a fellow child of Bhaal.

[8] In Baldur's Gate II, several characters from the first game reappear, of which the following can join the player's party: Imoen, who grew up with the protagonist in Candlekeep;[48] Jaheira, who, with her husband Khalid, was a friend of Gorion's;[56] Minsc, a warrior who carries with him a hamster named Boo;[57] Edwin, a Red Wizard of Thay;[58] and Viconia, a dark elf cleric.

[8][58] There are also many new NPCs who may join the party: Aerie, a winged elf who has lost her wings and was sold to the circus by slavers at a young age;[59][60][61] Keldorn, an older paladin and a powerful and respected member of the Most Noble Order of the Radiant Heart;[62][63] Mazzy, an honorable halfling fighter and "the nearest thing to a paladin that a halfling can aspire to";[63] Nalia, who is of the upper class, but, though conscious of class distinction, tries to help those less fortunate than herself;[64][65] Valygar, who is of a family noted for its talented magic-users, but hates the art;[66] Anomen, a member of the Most Noble Order of the Radiant Heart, and whose wish is to become a full knight;[66] Cernd, a druid;[66] Haer'Dalis, a tiefling bard and one of the actors of an acting troupe;[63][67] Jan, a gnome, of the Jansen family;[68] Yoshimo, a thief from the land of Kara-Tur;[68] and Korgan, an evil dwarven fighter.

[49] In the slums of Athkatla, a man named Gaelan Bayle offers the party the help of a powerful organization, who can find Imoen or Irenicus for the large sum of 20,000 gold pieces.

Back in Athkatla, the party raises the money necessary and receives assistance from whichever organization it has decided to work with,[51] and gains passage to the island on a ship sailed by the dubious and treacherous Saemon Havarian.

[10] Co-lead designer James Ohlen wrote that having a completed engine meant they could direct their efforts towards producing content, instead of focusing on "basic functionality".

They would pass this concept map to the artists, who added models to it, beginning with the largest objects and ending with small items such as individual pieces of furniture.

Muzyka also said that "a designer might submit a level description and receive it, art complete, a month later ready for scripting, but missing some key features (almost always a door).

City renders took from 18 to 24 hours, though they used hardware that was powerful for those days: multiple Dual Pentium IIIs at 500 MHz, coupled with 512 MB of memory.

[76] Muzyka wrote that "because of its immense size, Baldur's Gate II was a tester's nightmare—this was compounded by the fact that we didn't do enough testing as areas were being developed".

Producer Chris Parker, writing in April 2000 about the upcoming voice-over recording sessions as Baldur's Gate II neared completion, observed that it could only start once story and dialogue were done.

[91][92][93] Also released was a Collector's Edition, which included the game, a cloth map, eight character-trading cards, a Black Isle Studios writing tablet, and an additional CD containing unique armor and weapons as well as music from the soundtrack.

[95] Baldur's Gate II: Throne of Bhaal, an expansion pack for Shadows of Amn, was developed by BioWare and published by Black Isle Studios, and released in June 2001.

Bundled with it are the game manuals in PDF format, high-definition wallpapers, artwork, avatars, and the Shadows of Amn and Throne of Bhaal soundtracks.

[120][121] In the United States, Baldur's Gate II entered PC Data's computer game sales charts at #5 during the September 17–23 period.

[123] In its first 14 days, Baldur's Gate II drew in revenues of $4 million across all SKUs in North America, a sales record for an Interplay computer title.

[138] The Verband der Unterhaltungssoftware Deutschland (VUD) presented it with a "Gold" award by the end of 2000,[139] indicating sales of at least 100,000 units across Germany, Austria and Switzerland.

[148] Baldur's Gate II received critical acclaim upon its release,[150] and is listed as the eight highest-scoring PC game on the review aggregator Metacritic (as of August 2024).

[152] Eurogamer lavished much praise upon Baldur's Gate II, and noted that "the story and quests are captivating, the gameplay tried and tested, and the overall feel is professional and entertaining".

[153] IGN's reviewer observed that many a time the game posed tough decisions that made him think, and also praised the clarity of the quests and ease of moving from one goal to the next.

[155] IGN echoed this statement, calling the difference between Baldur's Gate and Shadows of Amn "like looking at a still oil painting, and then turning to see the scene in living motion on a big screen TV".