I don't know where else you have posted this, but welcome to the Big Leagues! 1st try win with under 5% losses.
PLAYABILITY: Very little. Siege engines and bows seal the fate of this Castle.
BALANCE: As above. Standard tactics. Minimal thought required as to where to attack.
CREATIVITY: No story (although there WAS an implied challenge). On Siege That! Maps, the storyline, Castle design and defensive integration are the only ways to shine creatively. The Castle itself is similar to many other web offerings, but the lack of story makes this scenario below average on the creative scale.
MAP DESIGN: Very similar Castle to many others. Successful Siege That! Castles are extremely difficult to make challenging. This Castle joins the fray squarely in the center of the pack.
STORY/INSTRUCTIONS: No story to speak of. Good storylines are imperative for Siege That! maps since they have so few other areas in which they can excel.
I give you the same advice as I do everyone else: forget Siege That! maps and make Siege maps - they will give you the creative freedom you need to make scenarios challenging. :)