Please give constructive criticism! If you would like more detailed images (like a closeup of the middle or the 3rd), just ask. I am only in the Gold league, so if you see something dumb, be nice about it and tell me. Thanks!
First off the Main and natural aren't too bad at all.
I don't like the rocks on the 3rd base. I just don't really see a point in them. They are to stop a fast 3rd expand but that base is already pretty open so it could be hard to defend for terran/protoss, but it's also up on the high ground so attacking into it, assuming you get your troops up there would be tough for the zerg to defend. Plus taking a third puts you a lot closer to your enemy, so it's going to be harder and harder to expand on this map.
The gold has 8 mineral patches? Most only have 6.
The base layout is just kind of boring. It's just a straight line across the map without any neat pathing. Just Up Down Up Down.
The watchtowers can see every path I assume? Usually that's not a good thing.
Try to make bases flow from one to another. They all connect to the middle of the map right now but you really should try to make them more interesting. Add some high ground around the 4ths that you can path on, or make the middle of the map high ground so you have to move up and down ramps to get to your opponent.
Also did you get bored of texturing/doodading it? You did those cool little features at 12 and 6 with the red rocks and such, but the rest of the map is just boring. Keep working on those aesthetics to make the map more pleasing to the eye as well.