What do you think of my concept art for the story I'm writing?

Your drawings are truly excellent; you obviously have artistic talent. I could imagine them in a coherent graphic novel where the story would take place in prehistoric times. If you have the story-line plotted, which you seem to have, by all means create it. Your artwork is really wonderful and will make the story -- with a bit more definition, possibly. Have confidence in yourself to use it in a unique story of your own creating. Good luck!