Pool of Radiance was one of a number of AD&D games which shared the same (or similar) engine, they were often called the goldbox games because they came in gold boxes. What made them so good was their tactical combat. Unlike Baldurs Gate and Neverwinter Nights, it was possible to plan out exactly effects like fireball because of a grid system and the turn based nature of the games. Also, fights could get big, like really big, with multiple screens full of enemies. Fireball fun!