Downloaded it, very cool! ;D
The internal textures.... well.. they are a tad stretched out, but I suppose it would take weeks to perfectly texture an enormous thing like that. The pictures were nice, though.
From a gameplay standpoint... sweet! A good Co-op "Defend the Castle" or a CTF "King of the Castle" is in order. Hey, even in single player I suppose you could load up all the windows with enemies, and just make it a target for an airstrike called from the ground.
One problem I ran into was getting stuck in the library. I tried to go through the narrow hallway with the silver-colored floor, but after going through, I would often fall through the floor and end up in the library again. Wierd, but it may be an isolated event.
Good work! It is good that people are making use of the improved implemetation of buildings.
A suggestion I have is that if you still like making castles, team up with someone who is good at making maps and make a map full of them. A nice island with plenty of forest, with, for example:
The main castle of a manor in the middle of large open fields with a couple farm houses scattered about, with the whole area of the fields enclosed by walls.
A very neat, royal-looking castle with a moat (since by building the map you have control of waterways). And with an animated draw bridge that just goes up and down to bridge the moat.
The obligatory evil-looking castle on a cliff on the ocean side (with jagged rocks at the base, of course). With a fairly steep hill leading to the main gates on the opposite side.
A castle on its own small island.
Okay, maybe I got carried away, but a map like that would be sweet for multiplayer, especially with some areas of symmetrical terrain for an even team on team game.