David, you definitely went for the drama and I appreciate that. I can see from your WIP posts that you struggled with the scale of your design and I do have to say that I still have a problem with it myself. I understand the concept of a lighthouse to be seen from the air and perhaps space and it is in concept very interesting. I do think that what it does here is completely upstage and almost literally engulf the inspiration for this competition which is the Tower itself - especially when the "petals" are open as in your image. I think it would still work if the design was scaled down a bit.
The conversion of the photo from day to night is pretty convincing, especially given the time you had to do it. It looks like you went beyond the directive of the competition and "designed" some buildings in downtown La Coruna as well
The lighting is well done and in some ways really makes me want to see more of what's inside those petals. And after seeing the sprinkling of lights you added throughout the image I wish more of the paths around the Tower were illuminated a bit as well.
Overall an ambitious image, and despite the scale issues for me I think a successful one. Thanks for sharing.