Persona 3 FES

Persona 3 FES is an enhanced re-release of Persona 3 for the PlayStation 2. It contains an estimated 30 additional hours of gameplay over the original Persona 3, most of which comes in the form of an epilogue called Episode Aegis in Japan and The Answer in the localization. FES was released in two versions: One version containing both The Journey and The Answer and the Append version, containing only The Answer.

Episode Yourself / The Journey
Episode Yourself, also known as The Journey in the English localizations, is an enhanced version of Persona 3. It includes the entire original game, but with several changes. The number of Personas in the game has increased, secret videos of the Protagonist's dorm mates have been added to flesh them out, and Koromaru can now be taken on a walk. Several of the Social Links have been modified slightly, such as Tanaka being available at a different time. Several new requests from Elizabeth have been added, as well as new costumes to be worn in battle. A new event involving Chidori Yoshino was added, and the way Naganaki Shrine functions has completely changed. A hard mode has also been added. Save data from Persona 3 can be transferred into the game, but only a few things carry over, such as Persona Compendium and Social Stats (Academics, courage and charm). Additionally, the items received for completing social links will also carry over.

Episode Aegis / The Answer
Episode Aegis, also known as The Answer in English Localizations, is an epilogue which continues from the end of Persona 3. The chapter is only available in one difficulty setting, which is supposed to be on par with  Persona 3' s Hard mode. The gameplay is approximately 30 hours long, and allows the player to control Aigis. The story follows S.E.E.S. on a new adventure involving a new dungeon that has distorted time (Conscious Time Loop) and trapped them inside the Dorm. It also introduces a new playable character named Metis.

Etymology
According to the developers of the game, the term FES stems from the English word festival.