what I liked about the Prime trilogy, was that each game's soundtrack had its own style. Prime had the more electronic-techno style, Echoes had more of a darker element, along with what seemed to be more focused on bass then Prime. Corruption was much lighter, and well rounded, and (like DS said) more like classical music than electronic like the previous games. The music from all 3 games was amazing, but Corruption seemed to shy away from what made Prime and Echoes unique. 'Yellow Valkyrie' was a nice throwback to that style.