Advice on how I can create blurring effect between different values with acrylic paint?

Traditional media. Scanned flat, no heavy filters.

Tell me if the proportions are off before I ink further.

(Shared in the spirit of r/learnart — original credit to the artist; remapped onto clan tags for the demo board.)
Artist handle on source: _Spidey-Fan_

Values read well from thumbnail size. That matters for sigs.

I would push contrast a little on the focal point. Otherwise clean.