You asked for a critique, so here it comes.
I've got good news, and bad news.

BAD NEWS FIRST: The ship on the right side of the screen looks really wierd, like it is bending or something. I can't tell why, but the way the lines are makes it look really crooked. And the city seems to be dancing. Try to work on drawing straight lines. Use a sharp pencil and be careful not to smudge. Keep in mind cities usually don't stay pristine, intact, and shiny when there's a bally going on nearby. Another thing you might try is to draw front, top, and side views of your ships before trying to do a perspective drawing. Trust me, it helps. Last, that explosion is among the darkest things on the paper, when shading it is important to keep light sources bright.

GOOD NEWS FOLLOWS: That ship in the upper right corner looks awesome. The missile looks really cool. You did a good job of shadow placement, and of shading the city. I like how you included the cities reflection, but keep in mind the water would also reflect the ships above the city as well. Finally, the clouds are awesome and almost tangibly cottony. This is good.

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Addendum: Overall, very good work.

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First:Thanks for the critique.

I get a little wonky with perspective at times.

"Another thing you might try is to draw front, top, and side views of your ships"

I did:
[link]

Even made a rough 3-d model
[link]

Ah well, I'm not an expert--yet.

Thanks again, and feel free to check out the rest of my stuff.

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"Whatever doesn't kill you, leaves you emotionally scarred." ~ Lioncage

Ah, I stand corrected. Forgive me, I didn't view the rest of your gallery before making the assessment. The reason I suggested the view drawings is because something in my head told me, "I don't think he was quite sure what he wanted that ship to look like."

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I've always had problems drawing that one from the front. also, i'm painting this one now, and im gonna upload the ship in the upper left seperate first. i just finished it so take a look when its up.

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"Whatever doesn't kill you, leaves you emotionally scarred." ~ Lioncage

ok now its up...for somereason it wouldnt upload earlier.

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"Whatever doesn't kill you, leaves you emotionally scarred." ~ Lioncage

Quite epic looking. I look forward to hearing your descriptions later