Hi Bucket, thanks for your time, i'll try to make a v2 soon, and change some issues you've found, like textures. About the light_env entity, there's one on this map, but I think it's not well placed, i'll look at that too, thanks again :)
Hi SniperPros: You know the actual design and structure are very good. Even the brushwork is pretty darn good. I think this could be a really fun map with just a few changes. The portal idea was pretty clever.
Cons: However there a a few things that would really improve the appearance of this map. The two biggest things are the lighting and the texture choice.
With all the white textures, its hard to tell where the walls end and the floors begins. I really think if you were to mix in some different textures it would really help players get their bearings.
Since your map has a skybox you should add an entity called light_environment. Here is a good tutorial on lighting that will help you give some realistic lighting effects to your map.
Notes: You have the fundamentals down pretty good, now all you need is to implement a few more advanced techniques and you will be surprised at the difference.
Again, I think the layout is excellent.