CastlevaniaBot is a plugin for the Nintaco NES emulator that plays Castlevania. If you launch it during the title screen, it will play through the entire game from start to finish. Or you can intermittently start and stop it at any point in the middle of a game and let it complete a section.
https://meatfighter.com/castlevaniabot/
https://meatfighter.com/castlevaniabot/