Hello Vampire Hunters,
I worked on packaging this week end, with the printable game box . Feel free to download the gabarit and makes your own Castlevania for Gameboy box.

As reference, I used the Castlevania Adventure gabarit files from Nintandbox. https://www.nintandbox.net/index.php/en and rework it with the Castlevania Nes artwork and text on Photoshop.