Would be interested in how did you make the mod? Using AI?
I just extracted the files with asset bundle extractor and edited the sprites in gimp. Depending on the shade sometimes a single layer of dark brown set to color dodge is enough to bleach the art, though in this case I think I had to do some additional tweaking as the guy was a different shade in some scenes.
If the game isn't retarded, and ngl factory games aren't, the sprites will all be easy to edit with reasonable pairings and little to no duplicates, but I've seen games with spritesheets that shouldn't be seen by human eyes.
Also, I never tried AI but I don't think it would work well. AI still struggles with lines and without terabytes of training data it would be extremely hard to get it to understand the spritesheet. This was a pretty quick mod to make, if I was dealing with AI I would have easily spent at least twice the time just tard wrangling the thing.
