You see, I know how you might see potential of decent gameplay in this map, but the overall artistic value is, in my opinion, rather low. Wool doesn't have such a nice texture, the quicksand might be a cool (kind of) idea but it doesn't fit the theme, what really helped me in improving building is understanding colors and how they fit each other. Try and work on palettes and shapes, add some smaller blocks (stairs, slabs, fences) to add detail and this map might have some potential. But as of now, as I see it, it needs improvement.
If you're building SO much based on retro99, just submit that map again, voitlà. No.
Come up with your own ideas, it's why you make an own map, right?
By the way, don't get me wrong, the map is yours you can do whatever you want with it and what the heck not, but I'm just giving constructive criticism, and that's how people improve, with criticism, with tips by who might or might not have a little bit, even that small bit of experience of someone else.