Woah, this map looks really cool.
Somehow, it reminds me of texture city, and shows some really interesting elements. The map has great design and shows some really cool ideas thought not possible (especially some jumps you can make).
A 3D skybox would make this map really really really awesome. But that's it!
Really not much can be done to improve the map, it mixes the perfect plan with the perfect textures and lighting.
This is a great map, so I definitely want you to keep up with the great work.
PS: I actually can't believe this is your first map. You must have spent tons of time into this level. Like tons!!!!