I've been having some fun playing a custom "score attack" mode that's possible to do on the 3DS version of Castlevania.
First, when I reach the level I want to do the attack on, I kill off all my lives and select Continue to reset the score to zero. Then I create a Restore Point on the Virtual Console menu. Then I try to get as many points with one life as possible on that level. I then record the score on the Game Notes app from the Home Menu. I then resume the game, reload the Restore Point, and try to beat that score.
So far my high scores are as follows:
Block 1 - 69910
Block 2 - 47460
Block 3 - 57880
If you'd like, you can try this mode and post your scores.