The size depends on which mapper chip was used for the game. Castlevania III (which uses the MMC5 mapper in the USA) nearly fills the cartridge space. You may

The size depends on which mapper chip was used for the game. Castlevania III (which uses the MMC5 mapper in the USA) nearly fills the cartridge space. You may be interested in checking out: http://www.nesdev.com/ http://www.nesdev.com/