(NES) Total Conversion Hack Castlevania 3: Aperture of Corruption

Started by Toffi, December 08, 2020, 11:20:05 PM

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 I am still following this and still loving every update. Huge strides are being made within the Castlevania Romhacking community here. There have been way too many cool looking projects for Castlevania that went unfinished and abandoned. Don't let this be one of them. You do great work Toffi!  :thumbsup:
Insert "Witty Text" here.

Xander max

Congratulations on the project! I'm impressed, first time I've seen talk of overlaying sprites in a hack! In the future I could share how you did it, for sure many people are curious.


Spring is in full swing. May the 4th be with you! It's time for another update from AoC's month development blog.

Starting us off is one massive level update. We've officially started working using the MMC5's extra bank space. This idea goes all the way back to AoC's first post back in 2020. Way back then the idea of doubling the bank space was seen as a distant impossibility. It took a while, but we've finally entered a new era of development.
What's magical about CV3 US version in particular is what AoC team calls the 'voidspace'.

During translation CV3 was taken from the famicoms VRC6 chip to MMC5 for the NTSC and PAL units of the game. Many people viewed this translation as a lesser version. The VRC6 used FM synthesis and the US version had less sound quality and was much harder than its famicom version. However that switch to MMC5 actually has one massive advantage over its famicom counter part. The MMC5 has a massive amount of space, far greater than the VRC6 version, in US builds a massive amount of static unfilled space was left in the CHR registry.

With some cleaning and bank swapping we can tap into that gigantic ammount of empty space and expand the game far past its original limits both graphically and mechanically. Currently the ROM size has been boosted from 311.2KB to 512KB, and can theoretically be expanded to a titanic 1MB at its maximum capacity.
So what does this mean going forward? Technically speaking the extra CHR space given will allow for more detailed levels, new stage specific enemy variants, higher quality DCPM samples, and more room for ASM manipulation.

Before we go, here's one last reveal...
The possessed hannya shaman's mask 般若 hides in the shadows. These accursed masks are rumored to portray the souls of women who have become demons due to obsession or jealousy. Their use in ritual kagura dances have possessed them with vengfull spirits looking for new wearer's to puppet. Collected by Dracula on his many travels; these foe's seamlessly glide through the air. In high number's they can easily become overwhelming.

Reply section:
Glad you liked the boss design Ok Impala!

I agree Googie. I can't wait to get a proper demo build up and running for you guys to play with.
I'm looking forward to comparing the our first build with the final one to see just how much the team grew over the years.

Thanks for the compliment Flaviogames. I hope we can reach that goal someday. ;)

No need to fret StarWyvern, progress is steadily growing and with the help of the teams development partner's were only picking up steam as time goes on. In the event that some major event stops progress plans have been put into place which should mean a prototype build (internally known as PRB_10.1a) would be automatically released.

If you have some extra info on sprite overlays I would be more than happy to hear about it Xander max! It's a great thing to learn and could provide a whole new layer of depth for a wide variety of NES titles if implemented using ASM. Knowledge is power!


this MMC5 expansion to 1mb is amazing, I may be wrong but I think it can expand to 2mb, so I could add a better sound effect when attacking with the whip and maybe better walking animation, congratulations for the work

Alkali Man OG

Man.... This hack is looking more and more incredible every month.

BTW how much of the hack is planed to have original sprites?


Awsome that you have more space now for a bigger castlevania rom. But we need more levels and bosses then cv3. I don't think we need more graphics, Gamers want more fun  :) or hell max this new rom size out and make 3 games, castlevania xx part 1, xx part2, xx part 3. I have a friend that makes multicarts for nes. And if you guys might do this in the future i could put all 3 games on a multicart like how ninja gaiden trilogy was for snes. Just an idea. the pictures look dope. Keep up the good work.


Having more levels is certainly feasible. At least, free space is not a problem, and even level length is probably highly modifiable. I can see problems emerge because of the transition between levels, for example. Or how to manage forked paths, which also involve a special "cut-scene" where the player can actually move. If adding entire levels appears to be too hard to accomplish, having longer levels can do the job to an extent.

Ok Impala!

Having more ROM space is a real blessing for ROM hackers. For Ember of Mana we managed expand the ROM too. Making it possible to create far more detailed and interesting maps. This not only makes a game better from a graphical perspective, but it also opens lots of possibilities for gameplay improvements. Great update Toffi!  :)




Stunning visuals! Good luck with this ambitious project.


Welcome! I'm back with a monthly update for June. This time around we've got some more programming progress to show, so let's skip the intro and get right to the good stuff ;)

Recently AoC teams got their sights on upgrading our graphical ability with a new automatic dithering process. With a few tweaks here and there we can automatically translate photographs and art into NES era. This gives the graphics team a new way to make stages and art pop both on CRT and at home.

For those who may not know dithering is a graphical technique that blend two colors together. It's one of the best ways to extend the color count without breaking the bank. Our ordered dithering system assigns pixel patterns to unique colors to capture more detail. One drawback of this system is that the lower resolution an image is the more noticeable the pixel pattern becomes. Below is an example of how big a difference this makes. We can turn what was once a measly 13 background colors into much larger set of 93 shades that we can use at once.

That means we can achieve a higher quality detail at a fraction of the tile price. To put things into perspective the level shown here takes up half of the possible space it used too. Over time we hope to continue down the pipeline of making larger more detailed levels in every way we can.

Now that we have the big stuff out of the way a few quality of life updates have been patched. CV3's items, enemies, and tiles are still being patched and re-done. This includes our phase 1 designs, which were essentially remastered versions of the original CV3 stuff.

For instance candles and hearts were re-done for AoC rather than having them become something completely new. They were just too iconic to change.

For the vets out there that worry some of your favorite enemies are gone fret not! We have the space to bring back some older enemy designs along with new ones, and many of those classic ghosts and ghouls will remain in Dracula's Castle. On that note what are some of your all time favorite classic enemies that NEED to show up in the last act? Feel free to discuss your picks down below!

(top is the old 2020 version and the bottom was made in 2022)

Hi Flaviogames, thanks for the input. I believe the max we can pull out of the system (at least what could possibly be used with the original CV3 MMC5/ELROM board) is 800KB's simply due to the original hardware. Using modern emulators and flash carts like the everdrive we can reach that maximum of 1MB only by switching the board from the EL to EW variant which bumps the CHR rom from 256K to 512K letting us reach that glorious 1MB. This was done way back in the early days of the project to prevent cart resellers from ripping apart actual copies of Castlevania 3 apart to make copies.

AoC's a total conversion hack Alkali Man OG, we are hoping to remake/remaster every asset.

I couldn't agree more Arcade-Elite. The main problem were facing right now with getting new content in is ASM coding help. Were severely understaffed when it comes to bit and bite manipulation meaning cool stuff (like custom level maps and new AI) has to wait for the fundamental stuff (original music, cutscene's and level transitions). The best way to speed up the process would be to get more help in.

Thanks for the support Nio, Googie, Ed and everyone reading this:thumbsup:


Awsome update it's good to see your team is still getting this game done. As for being understaffed maybe you could put a post in the help wanted section. The main people that i think did the best Castlevania hack's so far are Optomon, Dr. Mario and crew that did the Castlevania Holy Relices game and Chorus of Mysteries. And 90 type of coloring options should make it easy to get your sprite work done
the way you wanted with less limitations i think. Talk about being skilled in making this game, good jobs guys. PLEASE keep up the good
work! Happy Hacking  :thumbsup: ;) :beer:


great update, I really liked what I saw, this will be a great game for Nes and the best is with a new look and more colors due to the technique explained by Toffi just above :thumbsup:

June 05, 2022, 09:30:36 AM - (Auto Merged - Double Posts are not allowed before 7 days.)

Toffi: would it be possible to have a higher level of the whip with greater range? a cool thing was if chite updates were the house phase until it reached the maximum and not perser the update when it loses a life ;D


Using better dithering techniques we were able to up the detail on the title screens stop watch.

Here's a quick sneak peak at a WIP library section to Dracula's castle.

Thanks for the tip Arcade-Elite, hopefully we can find more interested people. As for dithering in sprite work, most of the time larger dithering patterns are reserved for bosses as the effect is harder to pull off on a smaller scale. Later NES titles used flat shading with only a few spare pixels to make objects more visible on CRT's. (These are Kick Master's enemies for reference)

Hi Flaviogames, it is technically possible to give the whip a longer range using sprite edits. 2 main factors would need to be assessed before attempting this. The first would be CHR space, sadly that's 100% used up for our current belmont bank. This means we can't give this extended whip any new graphics ala the chain whip. The second would be if the data for said whip may be retained during the death, while challenging this is also technically possible using ASM edits. Coding would be the biggest factor in adding these, currently other aspects and features are being worked on (ala the sound bank and still screens).


Howdy folks I'm back with another round of monthly updates. This time around we have new stage demo's and technical details ready to go.

First off, since June's post the dithering engine's helped elevate some of the stress from stage design and because of it I've been able to boost the detail and experimentation of each demo going forward. This means greater detail at a fraction of the time it used to take, making more detailed designs possible.

One of the main drawbacks to this process is the amount of CHR data is takes up. The larger the graphic, the more costly it becomes. Replicating 'semi realistic' environment's while rad was hard to justify. In order to balance out the two we needed to blend dithered and flat assets in a way that became less CHR heavy while remaining more repeatable.

This design is a forbidden greenhouse within Castle-vania, marveled for both it's beauty and danger. The waterfall sections were done in a similar manner to the background, combining photograph's and animation in a way that stylistically meshes with the environment.

Next up is a 2.5D stage test of an insane asylum left abandoned on the outskirts of Walachia. With winding towers filled with cells and open pavilions for patients to wander this concept has been a blast to work with. Feel free to let me know what you think about the effects below, as always I am more than happy to chat or answer any questions you guy's have about things.

Thanks again for tuning in and I hope to share more progress again soon.

Alkali Man OG

The shown tilesets look amazing, but the edges of those "2.5D" tiles look off when cutoff


This may have been asked already, so I'm sorry if this question has been addressed before, but will this hack be compatible with the Improved Controls hack for Castlevania III?
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