Big dioramas are always fun to see. They have the immediate WOW factor and when done well, are hard to beat. The problem is keeping the standard throughout ... in the scene, the figures, the vehicles, and the structures.
After all the work you have done here, the floating building is too visbile ... but not all is lost. Some rubble, dust or even some weeds/grass can hide this.
Another thing that stands out for me is the rubble. Where did this come from? Is it a neighbouring house? Whys has this flying rubble not done some damage at the side of this house?
Where you caught some bits of the architecture like the corner stones beautifully, the wooden outer frame and missing spouting also are quite noticeable.
Small details and some may say picky details, but its items like this that make a nice dio a great dio. You have so many things that are very well done, the few misses drag down the overall quality.
On the plus side ... the roof, the composition, the vehicles and figures are excellent. It takes a lot of dedication to build a big dio. Well done.