This is an amazingly realistic castle. I love all those tiny little details like the outer wall with its towers and roofs, the gates and the narrow windows. The keep is nicely done and the construction site of the main tower is breathtaking. The siege is very beautiful as well. The ladders, the shelter of the cannon, everything.
I have one tiny thing to criticise, because I think the castle is supposed to be historically accurate (otherwise I would not mention this): The helmets (nasal and great helm) and the shields (especially the kite shield) of the defenders. They were not used in the 15th or 16th century. Even the grilled helmet does not fit, since it was hardly used in combat. As for the helmets, you should use the Sallet of the Dragon masters and/or the Barbute of Knight’s Kingdom. Concerning the shields, well that is a problem, as LEGO has never produced a real late medieval shield.
Check this out: http://www.tempus-vivit.net/bild/1027