1. Very bad terrain / destructible / doodads. What's up with Waterfalls? Couldn't you make it worse?
2. Only two units in entire map drops items - inbalanced drop.
3. This is not melee map since you started using Custom Units.
4. Three Gold Mines at both start locations? Why not increasing one gold mine's amount of gold equal to three gold mines? Afterall, you must have only one gold mine nearly you, others must be quite far and protected by creeps.
5. The idea of spamming 13 items into one spot is horrible.
6. Creeps doesn't fits Tileset you are using, for example: You have Lordearon Summer Tileset and you are using Northrend units as Nerubian Spider Lord.
7. Too low amount of trees for receiving Lumber.
8. Change controller of Player 2 to user. Scenario > Player Properties > Player > Controller section and switch Computer into User. So people can play it in internet.
9. Your custom unit is badly done on Object editor, let's say it's health points and selection scale.
10. You set Start Locations too close to Gold Mines.
11. At the start, when passes some time, not much, Player 2 is being attacked by Red Dragons (Whelps too), that means, creeps are too close to your start location.
12. Very bad description, at hiveworkshop too.
I rate it by 1/5 without any mercy even if it's your first map. Hope you'll improve yourself.