It's an anime industry tradition that stretches back to the original "Mobile Suit Gundam": re-editing and adding new animation to popular television series in order to transform them into feature films.
The latest anime to get the "compilation" treatment is "Eureka Seven," a 2005 sci-fi series about 14-year-old mecha pilot Renton Thurston and his relationship with the mysterious Eureka, an alien who has taken the form of a young human female. "Hi-Evolution 1" is the first in a planned trilogy that's set to retell the tale of the original 50-episode series.
The original "Eureka Seven" followed in the tradition of giant-robot franchises like "Gundam" and "Evangelion" by combining mecha action, romance and a fair helping of teen angst. Its twist on the formula and a large factor in its popularity was the way it incorporated popular music, with bands such as Supercar and Denki Groove on the soundtrack and copious musical references scattered throughout the script (penned by popular anime screenwriter Dai Sato, who also wrote this film).