There's definitely room for improvement in Fading Shadows. It has a reasonably novel concept, reasonably well executed and it even looks and sounds reasonably good, too. The tacked on narrative does no favours for the game's identity, which should perhaps have focused more on being true to its puzzle game roots.
The levels aren't too bad for length, but there aren't quite enough given the lack of worthwhile extras – you're pretty unlikely to ever experience the multiplayer. It's worth a shot if a relaxing ball rolling puzzle game sounds like your ideal PSP experience, but it's unlikely to stay in your active playlist for long.