So far, it looks and feels like a Sly Cooper game. Sly seems more talkative though compared to the first few games.
I love how you can change costumes to change into a robin hood version of sly with "L2". I don't know if thats been in the series before, since I haven't finished sly 3; but its fun and easy to aim with the bow and arrow they provide you with.
For the most part the gameplay hasnt changed, its only added new things like the costumes I think. Except when you die or fall down, it backwards in time like "SSX" where it goes backwards to your last position and takes a chunk out of your health meter.