The more examples you give the better. If you link to a research paper or two, even better. That would give @David_Tschumperle and the other brilliant minds of G’MIC good reference points.
I improve a bit but metapixel Generates dither 
Looks better. Would smaller sprites help?
The texture/dither is due to an error of the program. This says me the author
http://www.complang.tuwien.ac.at/schani/metapixel/
I did it
convert $NOMBRE.png -dither None -remap mosaico.png png32:$NOMBRE.f.png
metapixel -w 8 -h 8 -d 1 --antimosaic mosaico.png --metapixel $NOMBRE.f.png $NOMBRE.w.png
convert $NOMBRE.f.png -resize 32x30 -scale 256 - | \
composite -compose difference $NOMBRE.f.png - - | \
convert - -resize 32x30 -scale 256 -contrast -threshold .5% mask.png
convert -size 256x240 tile:$NOMBRE.f.png tile:$NOMBRE.w.png mask.png -composite $NOMBRE.w.png
convert $NOMBRE.w.png -dither None -remap mosaico.png $NOMBRE.bmp
2 Likes
now color 
These sprites generate them with imagick
game 8bit for arduino/qudino with tvout
This is proving to be a tough issue it seems. Would restricting the palette used make it better? The H shouldn’t show up.