Sonic Rush Adventure review at Zentendo.

"Until recently, it could be argued that the Sonic franchise was in the dumps. Even one of the executives behind the franchise stepped forward and admitted that drastic changes would be needed to revitalize the dying franchise. Though two other titles coming out this year will probably improve the hedgehog's image, niether are a dedicated title solely devoted to Sonic. Sonic Rush Adventure is the second Sonic title for the Nintendo DS, but it dares to attempt to take the franchise in a different direction. Rush Adventure blends 2D and 3D gameplay along with the element of exploring an entire sea of islands (much like Phantom Hourglass) in order to produce a unique Sonic title."

Full Source: Zentendo via Gonintendo