I think you could really benefit from practicing draw hands, feet, claws etc. I know, I know they're a nightmare but you really do need to nail them if you want to your art to stand out. I say this is nearly every critique, but my only advice is to go and look at an animal similar to what the pokemon (or subject) is based on, and draw from there. Or look to other people's art for reference.
Try and keep your shading more smooth, since you're not using a fuzzy brush that means your shading needs to look really clean as well if you want it to look professional - this is especially noticeable when working on a smooth surface as light will just not reflect in a jagged manner from that sort of surface anyway. Look at this
gliscor painting for reference, notice how the smooth shading makes the whole image look cleaner? This doesn't apply to all artwork, but I think it certainly lends itself to the sugimori-esque style of your work.
You lineart looks jagged around the edges, I'd suggest turning your pen pressure settings off if you have the option, and also (sorry I only use photoshop so I only know what to do from there) adjust the
brush-tip shape settings in photoshop so that the spacing reads 1. This should help clear up the lineart a bit. Also drawing on a large canvas and scaling it down may help.
I actually like your MAC entry quite a lot, except for that blue line which shows the outline of the front leg. I don't think its necessary and it clashes with the style of the piece. Either remove it and fill it with the base blue colour (people will assume the leg is there anyway from the position of the spike) or erase the line and let the black background fill the outline.
Some decent artwork here mate, and you deserve more comments. Hope you don't give up as I can understand how frustrating a lack of feedback can be! Keep at it!