Flavio,
congrats on the image. Your building design is one of my favourites - can't wait to see it up close in the animation.
However, I think it's a shame that my eye keeps getting drawn to the low res terrain texture, as it's one of the lightest parts of the image. I would've liked to see it developed a little. I also feel the rowers and calm water combine to give the feel of a boating lake rather than the sea. (and would rowers be out that late at night?!
)
I feel you could've chosen a view that explains your building better, or at least shows more of it. I hate to say it, but I feel that the second image (the sketch study) is the more successful of the two images you've posted in terms of colouring and focus, as there's little in it to distract from the tower and building.
Looking forward to seeing inside the structure in the animation!