QuickNES is a very inaccurate core, except for the sound. The sound is (usually) the same as when you play on an actual NES. NESHawk is preferred over QuickNES because it's more accurate in terms of visuals, but the sound is slightly inaccurate. I'm just letting you know, partially from my experience (I am blind, so I can't tell what the graphics are like.)
Thanks DJ and Memory. The reason I used QuickNES is because I'm running a bot. I will try to resync the solution to NESHawk, although success is not guaranteed because of Castlevania's horrible handling of RNG.