This is a map of two distinct halves.
Playability: When I launched this map for the first time, I was looking forward to a serious invasion, or wave of invasions, to defend against. However, it didn't happen. There was only one invasion at the start which was quickly crushed. After that, nothing. No win criteria, no follow-up attacks to defend against and very little for me to do whilst playing. I have to give this a low score here simply because there was nothing really to do.
Balance: In light of the above, and even though playing on the hardest level, this is simply too easy. You have MASSES of troops to defend with and a stalwart stronghold that will take some work to break into. This set-up could easily hold off against a combined invasion of 3,000 troops or more, which would be an excellent map to play. A hundred or so troops, most of whom were weakened or killed as soon as they appeared on the map as the signpost was so close to the castle, were no force to be worried about. This map really needs extra work done and resubmitting: if so, it will be a great map to play.
The other half...
Creativity: Not an original idea but the thought of testing your defensive skills with a castle/fortress behemoth and hundreds of troops lilke this could be interesting. I'm being lenient giving this a 4 for creativity, as the other areas of the map are much weaker.
Map Design: Terrain is quite well done, lots of good areas of landscaping. The castle itself is unique and enormous, lending itself to the type of map. This is a great castle in it's own right and the amount of work done by the author is worthy of praise. Overall, a very well put together map on a massive scale.
Story/Instructions: Nothing really here to support the map, i'm afraid. Not much of an intro on the download description page, nothing of any real substance as the game begins to play and nothing in the zip file. I really can't give this a higher score, bearing in mind the lengths some authors have gone to in providing a comprehensive introduction, story and additionals (pictures, word docs, etc, etc).
In summary: The author really needs to add more invasions in here and maybe concentrate on making it a fighting map. With a decent write-up and story, or something to introduce and promote the map more, this could score very well indeed and be a recommended map to download. Please, consider the above and resubmit, as I would love to play this if it were more of a challenge. I will glady re-review this if amended, as it has loads of potential.