Hi Aibolit,
No shame in being obsessed with batman.
However, in my opinion your value studies lack more contrast. (I think its called contrast at least). You seem to have a fine understanding of digital blending techniques. But you need to get more dark grays in there, and maybe even some clean black to spice them up a bit. Right now they're too light.
A way to force you to do this could be to put in a clean black where your reference photo have the darkest value (even if its not a clean black) and lay down pure white in the areas where your reference photo have the brightest value. When that is done, you can work on all the values in-between.
Hope it makes sense.. If not, please ask me to elaborate

oh, and I am by no means pro myself, so please do take my advice with a grain of salt
Keep up the good work!