Simply raised the structure and added some minimum details. I indicated a path leading up to the building to add some interest. If you look closer at the waves at the bottom you can see I actually used the default maple leaf brush to mimic scattered waves, and went back in with a smudge tool to kill a few hard edges here and there. (Fig.13-a)
Toned down the killer wave. It still looks tall but at least not like some tsunami from hell. Other than that I simply laid down patches of textured shapes with a large brush on a layer and carved out the details with a small eraser. (as mentioned before) (Fig.13-b)
Further detailed out the main structure. Added windows and a flag, also threw in a soldier on the balcony to make it more interesting. Refined the building in the back, and popped that flying thing up there just for kicks. (Fig.13-c)
Made the booth larger so it looks like the guard can fit in there. The rest is pretty straight forward, just detail out the characters and the bike with a small brush. The chick's gotta have some insane strength to lift that cannon, but I actually like it that way. Who knows, maybe she's a cyborg. (Fig.13-d)
The painting was almost done. I gave it a once over just to clean up some minor areas that were still bugging me. Threw in a layer of smoke effect in front of the bike, adjusted the levels, sharpened it with filter, and the thing is finished. (Fig.14)
Of course there're always room for improvements and revisions, but for now the piece does what it needs to do. I hope some of you find this helpful. (assuming you can look pass my pitiful grammar) It was great to do something outside of work just for fun.