DnD, D&D influenced Baldur's Gate

Baldur's Gate is licensed Advanced Dungeons & Dragons, running the 2nd Edition rules as its engine, and that is the whole reason it plays the way it does. What is literally the tabletop game: THAC0 and armour class, the six ability scores, the class and level structure, spells memorised per day (Vance's mechanic, arriving by way of Gygax), saving throws, and the Forgotten Realms as the setting, with Baldur's Gate, Candlekeep and the Sword Coast taken from published campaign material. Filed HIGH because the debt is not thematic. BioWare's real invention was the pause-and-issue-orders interface that let a turn-based rulebook run in real time, and everything it was running was somebody else's rulebook.