When you create your own game idea and your own IP without riding on the coattails of the Castlevania series, then you can have as much ego and hubris as you like. Until then, kindly check yourself.
What you've made is nothing more than the equivalent of a fan game for Castlevania (changing things here and there to avoid legal issues). I'd argue that rom mods/hacks made by far more talented individuals/teams have a greater precedent for this style of gameplay while also including original compositions superior to whatever you have offered in your demos.
When you're coding in 68k assembly language, then come talk to me about gamedev.