I haven't played previous Bloodrayne games, but I think if you go into Bloodrayne Betrayal as an original 2D action game starring a female damphir that uses Bloodrayne license you'll have a better time. It's a mix of the dashing abilities of Mega Man X, the linear stage based gameplay of Castlevania and the movement of later Metroidvanias.
Some of the creative talent behind the game, including the director, also worked on Double Dragon Neon and have gone on to form Yacht Club Games to make Shovel Knight. (So if you're waiting for Shovel Knight, definitely check out this game)
It's only $10 on PSN and XBLA now, but I would recommend the Xbox 360 version if you can get it because the game feels like it was designed for the Xbox 360 controller with its analog stick and triggers for dashing. I think most players would have a harder time using the PS3 controller because it feels looser.
Once you beat the game, you can unlock the 8-bit soundtrack. Here's my playthrough of the early stages. (Protip: If you press attack right when the coffin lands, Rayne will kick it open)
Stages 1-4
http://youtu.be/6zpEEKKi_TE
Stages 5-8
http://youtu.be/Gsi3axrxYEc