as the two before me said;
Vanquish is pretty unique, but not for everyone since the Campaign is maybe 5 hours long.
Enslaved is the more Cinematic 'Post-World' Experience. it lasts 8 Hours and is kinda the oppsite of Vanquish -> instead of deep gameplay, you get a deep story.
Castlevania ist kind of the hybrid Game of the 3, the Story may not be as deep as it was in Enslaved, and the gameplay isnt as Pr0n as in Vanquish, but both sides of this 15-20 Hour Medal can satisfy your needs of story and gameplay.
So, its up to your likings in the first place. :<

I'm a Foreigner, and as such, i am grateful for everyone pointing out any mistakes in my english posted above - only this way i'll be able to improve. thank you!