Not bad at all to be your first map
Some comments:
1. Another player managed to get 3 markets somehow, I dont know how. Maybe he built them at the same time.
2. It might be an idea to add some new, more expensive towers, to match the increasing gold incomes.
3. I missed having a "quest" with information on the map, like how many levels there are, when is air, tips, contact information etc. You dont always the remember what's on the intro screen after you've started playing.
4. I got alittle confused with the Keep where you can buy several workers. The description of the first worker made me think I could gather resources with it somewhere. I didn't recognize it to be the regular builder
And was there any difficulty voting? I dont really remember
If not, and if you know how to do it yet, then I suggest you add that
I dont know when they removed the map ratings from this site, but I would give your map a 4 if I could.