This one is based on a story and a game, "Castle Phoenix" which is a continuation of Castle Perilous. It's a mysterious techno castle, so advanced that to the current inhabitants it seems almost magical. Lots of mystery.

Anyway, this is my interpretation. I'm kinda happy with the castle, and at the same time not too pleased with the bottom portion. I'm also not sure of the background/world. Not sure of a good POV or scene or anything. Anyway, ideas? Opinions?

Want to finally wrap this one up.

i like the look, may i suggest a slight camera tilt so you are looking from slightly below, that should make the spires loom above. also maybe a mist line, or flare from setting star along the horizon to blur the sky/sea divide. 
i like the lighting, makes the textures glisten nicely. and for me the bottom looks cool, as if its the industrial foundations, holding up the gleaming top half. maybe a few small flying craft buzzing around.

The model is cool, nice work. In my humble opinion, i would tilt the pov pretty extremely up or down as i hate to see that bryce horizon line, especially in an ariel scene. 
Also theres a guy here Mirek (tse60) ,on his website  Tse60.com he has some excellent bryce skies to download for free which are perfect for this kind off pic!

I think a slightly curved horizon would be great. The model looks cool as it is.