The graphics downscaling, despite being ripped graphics was actually quite a lot of work.
I made the decision from the start that I want to keep all the detail, but this means some characters or backdrops might end up with different colored costumes/details.
I looked at quite a few different sprite character rips and found that 5 or 6 skin tones is the most any character uses, so I made a range of 7 skin tones, which covers everything and has a little room for variety amongst character skin tones. On top of this the "white" Im using also works in with the skin tones, as does the grey.
Blue is the most prominent color apart from the skin tones, so I gave that 4 tones (+ dark grey and white also work in that color "range"). This left me with a few colors left to try to cover the rest. There's actually only one yellow, but it was also chosen to tie in with some of the skin tones, as is the red.
The big "trick" to downscaling graphics to lower color depth in my opinion is making sure youve got enough colors that work within a particular "range". From a palette of 16 colors its entirely possible to get 4 or 5 colors with at least 4 or 5 colors within it "range" and a range with 6,7, or 8. Obviously there's no exact rule here, but its how I go about things.
Backdrops are done the same way, only with an extra 16 colors to hand pick. When something cant be recreated exactly then I'll change its color as discreetly as possible.
As for the practical side, PaintShop Pro is my 2d art program of choice. A lot of the work is using the color select tool and selecting the right color in the my palettes "range" Im using to retouch the original graphics with.
A peron will get much better results this way than letting the software downscale itself as they have complete control on how things end up, and you dont lose detail.
Anyway, long winded explanation, but it's a long winded process
