Hi all! I decided it was time to start documenting this idea to organize my thoughts and get some feedback and advise.

Concept

A stage expansion for the original 8-bit Casltevania that extends the game and adds some new content.

Intended Changes

  • Swap around 2 bosses.
  • Split Block 4 (Stages 10 thru 12) into separate levels and pad them with some new stages.
  • Split Block 6 (Stages 16 thru 18) into separate levels and pad them with some new stages.
  • Add 2 extra bosses for the new blocks.
  • Add a new song.

It would end up looking something like this:

Block 1 (Stages 1/2/3) Phantom Bat, "Vampire Killer"
Block 2 (Stages 4/5/6) Queen Medusa, "Stalker"
Block 3 (Stages 7/8/9) The Mummies, "Wicked Child"
Block 4 (Stages 10/A/B) Gillman, "Walking on the Edge"
Block 5 (Stages C/11/12) The Wolfman, (if I can get permission) "Howling Hybrid"
Block 6 (Stages 13/14/15) The Creature & Hunchback, "Heart of Fire"
Block 7 (Stages 16/17/D) Death, "Out of Time"
Block 8 (Stages E/F/18) Dracula, "Nothing to Lose"

So stages A thru F would be brand new ones.

As far as game play, I would like to consider making some alterations based on some of the early design documents found in the "History of Castlevania" digital book that came with the Castlevania Anniversary Collection.
I think this would mostly consist of adding new power-ups and sub-weapons and switching around how some of them work.
If I wanted to get really crazy, I'd want to try adding in the diagonal whip attacks, but just expanding the stages and adding 2 bosses seems like a huge endeavor.

Bogaa gave me some good input already that I'm going to look into info to start things off.

But if anyone has any other suggestions, feel free to post!

This looks promising.

I know there are a couple of docs about music and enemy data (archived by RHDN). And you might be able to learn a thing or two from the hacks of Optomon, Dr. Mario, et al. Chorus of Mysteries and Holy Relics have a lot of changes.

Also, Castlevania Modding is a good resource. But you might want to check NesDev for technical info.

As far as game play, I would like to consider making some alterations based on some of the early design documents found in the "History of Castlevania" digital book that came with the Castlevania Anniversary Collection.

Sounds interesting. What kind of ideas did they have?

Since I was mentioned I had like to make my inputs more clear on the idea. It is possible to add new entry for doors, checkpoints, secrets and entities.. (What would make a new block)
You could do that in the disassembly where it should also be no issue to move things to make the space for it.

Since the tables you like to address are all editable in staks it would make the tool unusable for the new block. In the game.ini file of steak you can address the location of existing tables but adding new entry like you suggest did never work for me.

You said you would feel comfortable to work on a new editor with game-maker to overcome the tool problem. A new editor will give a lot of opportunity for many things.

Making this changes as your first take in assembly seems too much. Would not recommend that at all for learning! Making a new editor for a new game seems more reasonable since you just look for the data to edit and you would not need to worry about all the things you can break while adding new things. Better focus to make a boss or item to see how that goes.

Instead of making all this changes in the last bank. I would just work on bank 5 and give the scenes and blocks more space to make larger areas. Then you will just have to update the enemy tracker data, cam-lock table and the stake game.ini for the new locations of the level data. In this scenario you could keep using stakes what will be a big help making changes to the levels.

In case you need inspiration how to edit enemies and bosses I share my hacks with the src files. You can ignore the music and MMC5 stuff.. in case you had like to use FamiStudio-Engine. This would not be possible in the vanilla game since I needed to add SRAM. You would at last need to convert to a mapper that supports SRAM. Or work with the original music engine. A other option is to just use my hack as a starting point. It is easy to remove all the code for the bosses and use a vanilla ROM to start fresh. Then making music is as easy as exporting from famiStudio and assemble along a new project.