Took five seconds to crudely destroy the lines between same shades of bricks. I don't think it looks flat.

Yeah thats the idea. It makes it look like some bricks stick out/in more than others etc.

I'm not sure but I think you'll find that erosion aside, there still would have been some randomness to the bricks such as http://www.toptenz.net/wp-content/uploads/2009/08/Troy1.jpg
Also good to mix up the shape geometry of the wall with some structural shapes such as in that image.
You wouldn't want vines all over every wall but there might be one bit where there is a garden inside and some vines have grown over.
Things like that can obviously help break it up a bit too although I don't know if that would have been allowed on the outer wall for security purposes...

@Mush: I understand what you're saying, but green's face is so busy I don't know where to put any more shading.
@TheChannel: I changed the shadows around green's eyes, but your bite seems a little too violent. I'm going for more of a gnawing. My fault though, I did name the thread Red bites Green.
@StaticSails: Those eyes are much better than mine. *yoink* But I don't want green to look like he's in pain; just uncomfortable and alarmed.
Here's my edit:

Things I changed:
implemented TheChannel's shading on green's eyes
changed the wrinkles on green's head(I'm afraid they might look more like cracks; they're supposed to be kinda stretch-ish)
changed red's eyes to look more like StaticSails's edit. also rearranged the face a little
changed red's teeth.
changed the darkest and lightest red colors(I think I still need to mess with the other colors some, but this is what I have for now.)

I'm afraid I might have lost some of the original crazyness I was going for with red. If I have enough fun with this I might animate it.

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Mush means lose the bright green strip on the right side. That especially is what makes him look disklike

Bumpdate! It has a tail now. Still very WIP. I don't know how did I mess up the mane. Ehhh, back ups are a good thing.

Good work so far I'm keen to see how it comes out. Still obviously some things to fix up.
From when I've riden horses there was 3 "gears" - walk, trot, canter and gallop.
So it might help to check out some reference of the differences in case you haven't already. Its actually very different what the legs do in each gear and it affects the way the resot of the body moves.

The main reason I mention is because the head stands out to me it does almost a double bounce as if it is cantering , but its legs look more like a full gallop.
So the head should remain failry still (slow movement) most of the time then drop suddenly and bounce back up suddenly I think once with each full run cycle.
And yeah I know its a big thing to redraw but I don't think it helps that you are just rotating the head to animate it.

I don't mind the perfectness of the bricks at all, it's just the way pixels become so .. physical. when a contrast between two surfaces is expressed as the collission between two color spaces the border between then is essentially 0 pixels, which I really like. when you put an outline anywhere suddenly the distance between two elements (in this case, bricks) is now 1 pixel. As zoomed out as this is that's like 20-30 cms of space between each brick. The effect is lessened by the low contrast of the brick color, though.

But by reducing the contrast and definition in some spots you get an unfocused effect that works well with syncronizing the brain in interpreting this the same way that it does a real brick wall viewed from afar. I think.

I just generally like breaking up outlines on big textured surfaces as to let the brain read more of the big shapes and read small details only where they matter. ' U ' ... at least that's my theory of it

I'm a still total noob but I think I was thinking something similar the other day.
I haven't had the chance to do an experiment but I was thinking that if for example a photo was taken of a black diagnol line on a white surface, and then scaled down to low resolution so the line becomes thinner than one pixel, then would the pixels of the line start to turn lighter grey instead of black because there must be both black and white in the sample?
In this case the black line would be the "outline" of the bricks (presumably some kind of shadow) which would probably not be so obvious from that distance if it was done with a camera (artistic license aside) - more likely it would blend in to be barely noticable in most spots.
Is that sort of what you mean Jad?