This looks fantastic! With the Scorpion Engine still in development, I hope things like bob / sprite scaling and zooming will be introduced as well as things like 'rope physics'. I discussed this over at BitBeamCannon, and they will probably look into it. Back to topic; hopefully CDDA tracks will be supported in the future, as this really screams a CD32 version; its that good!
Also, is a chance there will also be a version after this based on the MSX release of 'Vampire Killer'? I always preferred that one over CastleVania on NES; it's got a bit more exploring.
Awesome job!