Alrighty, this is my first ever critique, so bare with me!
First off, I love the way you did the emotions. You can really see the determined, yet fierce and angry gaze in the leaping dog, who I'm assuming is Blu. Lucky looks really shocked and horrified as he stares at the unknown enemy. I also love the shadowing and it really looks like the end of an alley way.
Now, I hope this isn't too harsh, but here goes. The main thing I see here is anatomy. Overall Blu's face looks good, but I would suggest making his body a bit longer to match the size of the head. His right, hind leg looks way too long and the left hind leg seems too short and tucked in. I would maybe try have one or both of the legs sticking out behind him. Now his front legs and paws look too big and could maybe be smaller and thinner. Overall, looks good! ^-^
Now the only main problem I see with Lucky is his hind leg. The haunch or thigh I should say looks too small and not positioned right. I would also suggest, for the back wall it just looks a bit too scribbly. xD
I hope this wasn't too harsh but I like it a lot and I hope this helps!
As usual, I'll start off with my usless ramble about the defects. Let's start off with Blu's, if I may. His head seems too big for his body, and the front paw nearest the viewer too large as well. On the opposite spectrum, the back leg nearest us it too small, as well as the tail by just a tiny bit. Also, the way the slobber drips out of Blu's jaws should be flying in the direction he came from, as he is in motion. Lucky looks fine, except for the bottom part of the mouth being too thin, without volume. The blood should also be darker.
I really enjoy the new background style you put on here, and would enjoy seeing more of it. Your shading is wonderful--better than I've seen a lot of artists do on here. This seems incredible to me.
Overall, it had a lot of flaws, but I enjoyed setting eyes upon it, and pieces like this are exactly why I watch you. I apologize if I may come across too harsh--I don't mean to offend, and plus, you are much better than I at many things.
(By the way, I enjoyed reading your RPing posts last night on Kugyay. The Gatherings are always so crowded.)
!! Only one word can describe this- E.P.I.C. The poses, the expressions (Blu's snarl=), the angle/perspective (very good joob with the foreshortening!), movement, colors, shadows, details (especially the tags look SO nice and shiny!)..... EVERYTHING ABOUT THIS. It's such a dynamic piece! And the comic book appearance totally is the cherry on top! What can I say? LOVE IT, LOVE IT, LOVE IT!!! THANK YOU JEN!