sebastianangelIt is a mostly manual process, to achieve a decent result you should not only analyze the graphics you want to adapt, but you should consider other variants of it and especially the original version

The first thing I noticed after I started testing was that there was a lot of information in this image that would inevitably be lost if I scaled it up, so the solution that convinced me the most was to find an optimal point to cut the image based on the original
NES framework:

But when comparing the result with the portraits of
Ryu's classic version, it was noticeable that he had become very big-headed or at least his head was the only thing that stood out:

So instead of just cropping it scale part of the illustration, as follows:

Although for this specific case the soft resizing was not the most indicated since the finish of the original work is rough or whatever.
Using the
ImageResizer-r129 tool, scale the image using the
Bicubic <GDI+> method already to its final size.

In this part I usually use
Color Quantizer, to get the best result, but looking for alternative ways to facilitate your task I discovered a very interesting function in
RIOT (Radical Image Optimization Tool).

With it you can filter the original image to improve the output results, in this example I used an additional color by mistake, since I usually work using images that include an alpha channel, this means that you have to configure a palette of 5 colors to be able to preserve the transparency.
Already with several different versions, it is only a matter of taking the best of each one and unifying them in a single illustration, paying special attention to the original version of the
NES, since it can take the greatest amount of resources to hide the limitations of the system.

On the other hand it is a waste of effort to use the real rom for testing. It is better to create a mockup with
NESImageConverter2, since it is fast, it is easy and it allows you to make changes efficiently.
That tape is very badly drawn, I fall from sleep xDChanging the subject, I can't quite understand why we should replace the mapper with
MMC5, it's a sincere question, I don't understand what advantages it offers over the mapper that this game is currently using
cartridge_romLogically, the artistic style used in a game should be the same from beginning to end, so although it may be a reference, I do not think that a version is created directly using the
GBA graphics
RealGaeaRegarding the endings, at the moment we are conditioned by the space for graphics, so we must consider it.
You have thought that if there are 9 players it would be necessary to draw
36 illustrations to fulfill your request, you are going to decompose the poor robot and then I will have to take him to the technician

I did some arts, maybe they can inspire or enjoy something!

Great illustrations!
