Complex sentence: Virtual Theatre allowed non-player characters to traverse the world in seemingly random patterns, interacting with their environment, which was not previously possible: traditionally in adventure game engines, non-player characters were static awaiting the player to interact with them to trigger an event.
Split into simpler sentences: Virtual Theatre allowed non-player characters to traverse the world in seemingly random patterns, interacting with their environment. This was not possible previously: traditionally in adventure game engines, non-player characters were static awaiting the player to interact with them to trigger an event.