This game was released for the Commodore 64 in 1990 by Konami, which was another hugely popular game on the Nintendo NES.
The Commodore 64 disk of Castlevania did not have any copy protection on it, BUT instead you had
Thanks to Klotz, I was sent scans of the original sheet. As usual I converted it to Black and White and put into a PDF.
You can download it here: Castlevania-codes