Playability: Whilst playing it was enjoyable, easy to play and lag free. However I felt it was very easy, I found a Bug in which the Computers would resign before I destroyed such important structures such as the wonder. I have looked into your triggering and adding a timer condition instead of a "is dead" would have been a lot more fair.
Balance: This isn't one of your strong points, However if you fix the bug it will become a bit more fair. I also felt the units were way to strong a circle with 2000hp just isn't fair. Besides even if they could kill the super units I had a bunch of other units to take their place. To balance this out simply remove the unfair characters such as the statue of Poseidon. And un-modify the units. Also I had way to much resources which was unfair because I could attack in minutes. the comp didn't stand a chance or have a chance to build up an army. Remember that in a real game the comp wont just sit there and wait. Often send raids or make the units build catapults or walls. Also when attacking you may want to add more units to the base. Because the computer will always add more units when under siege.this is also due to Because most units that die in the first wave of attacks were the only defence, and I could wipe out the structures with ease.
Creativity: I did enjoy the map however the concept has been done many times before. The cities could have had a little more eye candy added to them. But all and all it was a decent map. I didn't see a reason behind the mass murder in the game adding a storyline would increase the fun and playability in the scenario. Remember to take into consideration the tips above, they will help a lot. Also look into aomh forums and other downloadable content they have some really good stuff.
Map design:I feel you have put to much effort in designing the Fort which player 1 controls. Outside of the fort was nice and some small eye candy. But the enemy forts had little to no eye candy at all. Remember to take the time to place a few rocks here and there and Put buildings together to make large structures.
heres a link to multiple guides to show you how to better your eye candy and general map designing skills
Story: Sorry but there was no storyline behind this map, Next time you may want to brain storm ideas and put them together to make a storyline which you can follow by using cinematic and character quests. Even adding a small detailed description in the objectives banner would have been an interesting read.
Other notes: This map could have been a lot better with some tlc. Even making the enemy attack you would have been fun.So I hope you keep trying and better yourself Good luck :D.