Fantastic !
I would estimate hat the visible parts of your castle have been built between 13th and 15th century
It really looks good and shows the evolution of defensive walls.

For the landscape, I don’t think you’ve lost. There is an option that just smooth the terrain you have built (sorry I don’t have the name in mind right now). If you search you’ll see that it looks OK

The draw bridge looks just fine and well defended, now I wonder where you will put the second door and how you plan to defend it. Between the two square towers ? If so, you might want to add some defense on the wall between those towers.

Keep up the good work ! It's just terrific !