Star Ocean: First Departure is an enhanced remake of the original Star Ocean. Yoshinori Yamagishi, producer of the series, stated that he wants the remakes to feel as though they're completely new games.
First Departure uses a slightly altered version of the engine used for Star Ocean: The Second Story with similar features, including prerendered backgrounds and 3D battle fields. Production I.G provided new artwork and animated cutscenes for the game. New playable characters have been added as well. There are new voice actors and extensive amounts of new, fully voiced dialogue. Some music from Star Ocean: The Second Story, such as that of the bonus dungeon and riding a bunny on the world map, are played during similar scenes in the remake. It also features a theme song: "Heart" by the Japanese group Asunaro.
Source: Wikipedia, "Star Ocean (video game)", available under the CC-BY-SA License.