Vivid colors, and so Tim Burtonesque. I grew up loving Halloween because of the autumn colors, the warm, yet mysterious and ominous feeling in the background of my mind, and this pictures brings all those childhood feelings flooding out again. From the yellow in their eyes, to the old wooden sign and fence, to the heroes themselves, it takes me back to a simpler childhood, and gives me a great feeling. Obviously, I cannot express in words what your picture does. As a writer, this makes me want to start on a children's story, that would be a classic. Vivid. I can't say it enough! Again, well done!

Now THIS is an awesome piece!
I love how vivid and bright the colors are, and how you made them to blend from right to left in 'heat' which adds to the feel of a coming evil. Your use of colors also adds to the effects of the shading and lighting which are on point!

You paid nice attention to details from the town and lake in the background, to the trees, grass and leaves. These elements also add depth and perspective to your piece which is very nice.
I see a lot of subliminal themes in this picture which add interest along with the depth: like the trees and extra villains that are almost hidden behind the main antagonists; the town, birds, and protagonists that are waiting for the up-coming danger; the road that shows how far these hero have gone to protect their home.
It's all nicely done!

I then love the composition in terms of the balance:
The cat and mouse are very outnumbered and out-larged, which makes them so much braver. I think that the way you have the cat and mouse more of silhouettes adds to the idea of it being a legend; they're left ambiguous which gives the idea of fantasy, or more of vision than of reality. Almost making them larger than life.

As for things I would change:
I would only say that the fact the town is so far away also means that it would be easily skipped over, and because of this, most visitors if they miss the town won't see what our heroes are fighting for.
A personal choice of mine would have been to highlight the cat and mouse only so they can contrast from the landscape around them; although it could be argued that their remaining in shadow
might add to their being smaller than the Gravelanders, in literal size as WELL as power. [Their being a smaller power and STILL being able to win the battle makes them even cooler, and adds weight to their actions: they have MORE of a fight.]
I just think that adding more light around our heroes would help to make them feel more like the ones being celebrated.

My other thought is on how the image itself is so small (Although I know it's a trouble with how the previews here go:
You're work is so nice that it's an injustice!
I think that it being bigger could make the image more impactful; it would be more like a big burst of color and vision that would get a viewer to go "Woah! What is THIS? I must look at this more carefully to understand what's going on!"
So I think that finding a way to make it bigger if possible might be a nice investment.

Overall I LOVE this work!
It's so imaginative and you pulled the idea off so nicely!
[It's hard for people to take the ideas in their head and actually get it down, so kudos to you.]

I certainly look forward to more of your work