The official Japanese PlayStation Blog has written an article as an overview for Odin Sphere Leifthrasir, and they have released two gameplay videos along with it.
Classic Mode (PS4 Footage)
“Classic Mode” represents the original version of the game, released for the PS2 in 2007 in a widescreen format without many of Leifthrasir‘s gameplay modifications.
Refine Mode (PS4 Footage)
“Refine Mode,” on the other hand, represents the refined gameplay systems and UI modifications for Odin Sphere Leifthrasir.
The blog post states that the game is not simply a remaster, and that a future Odin Sphere Leifthrasir feature on the PlayStation Blog is planned to introduce the game’s five heroes and the setting.
Odin Sphere Leifthrasir is slated to release in Japan on January 14, 2016 for the PlayStation 3, PlayStation 4 and PlayStation Vita. The RPG remake has also been confirmed for a North American release in Spring 2016.