What this hack features:
Sram saving, no more passwords, it saves everything I felt is important even what loop you're in. I did the lazy version and just replaced the "password" jump with a jump to my loading code and renamed it "continue". I set the cursor to default to continue so you have to press "select" to erase your data making it difficult to erase your game by accident. It saves when you start a new stage, when you enter a new substage (going through one of those mid-stage doors) and right after you die, all automatically.
All stages are played in sequence giving you the full experience. No more choosing routes, now you get to play every stage in the game! Don't have time to do it all in one sitting? Worry not! Because there's sram saving so you can turn it off and come back to it whenever you feel.
I changed most of the game palette data, I wanted to get rid of that whole cartoon feel and give it a more realistic look.
Alucard is now the main character with the freeze attack and mr belmont is the backup character that you start your new game with. Both characters always have fully powered up weapons no more need to pickup weapon upgrades (I had to disable it due to a bug with alucard). Since you play every stage you can pick up any side character you want, yes you can have two alucards if you want. Whenever you pass through a substage door or start a new stage / die, alucard's weapon reverts back to the freeze attack so don't worry if you pick up the clock weapon.
I changed which song is played at which point of the game, this is merely a preference thing.
I changed the title screen from a bunch of japanese kanji into what I think is a nicer set of tiles (see above screenshot). Again, preference.
This indeed runs on real hardware, this playthrough was recorded from an av famicom with a converted madara vrc6 famicom cartridge.
The debugger used to locate ram addresses, locate code I want to change, and check my inserted code was fceux debug build. ReVamp was used for most of the palette changes but still a lot of palette changes I had to do manually. yy-chr was used for the tile changes of the title screen. Winhex was used for ending credit and title screen text changes. All programming changes I just typed myself in hex in notepad and inserted using a hex editor.
Will I release the ips? No, I don't feel like giving out this much work freely. But for anyone who's interested in hacking away at castlevania 3j here's my hacking notes so you can make your own awesome hack! (I want to inspire more people to learn how to do this):https://www.mediafire.com/?zdik4tf5iw3ng77