The brown isn't really working for me. I'd say try to find a better grey, but in GSC all of the greys were purple and brown. Maybe try something darker, like Skarmory or the second shade on Onix or Steelix.
The main thing though, I think you should try to not use the grey as the darker shade of red, or the red at the dlighter shade of grey. When a Pokemon is several colors, its best to try and use white and black it shade instead of the two colors, unless the colors really go together. Something that is one color like Geodude is ok to shade with two colors, but red and grey should not. Like on his arm that's downward, try white as the highlight instead of red. Same with the legs and shoulder. The hair should be all red, with black as shadows and black dithering in some parts. But otherwise it's really good.
Sorry if I made it sound like there were a whole bunch of problems. I just feel like its close, but not quite.
Also updated ghosts. Changed Banette's pose to be less boring and messed with the shading.
The main thing though, I think you should try to not use the grey as the darker shade of red, or the red at the dlighter shade of grey. When a Pokemon is several colors, its best to try and use white and black it shade instead of the two colors, unless the colors really go together. Something that is one color like Geodude is ok to shade with two colors, but red and grey should not. Like on his arm that's downward, try white as the highlight instead of red. Same with the legs and shoulder. The hair should be all red, with black as shadows and black dithering in some parts. But otherwise it's really good.
Sorry if I made it sound like there were a whole bunch of problems. I just feel like its close, but not quite.
Also updated ghosts. Changed Banette's pose to be less boring and messed with the shading.