Ok, this map most definitely rocks. It really made me look forward to Fortress Forever.

Besides some of the proportions being a bit too vast for HL2DM (you can tell it's made for the probably faster runnings speed of FF) the layout is somewhat smooth.

My complaints, visually, are the boring lights. Artificial light sources seem to be gray (white) only with no color or mood to it. The sunlight comes in nicely and I understand the "visibility first" approach, but some of the corridors look absolutely fullbright, not even the ceilings have a darker tone, which breaks the atmosphere completely.

I also noticed that cubemaps aren't working! Don't forget to turn on sv_cheats 1 and reload the map after buildcubemaps has run. Also it seems that you shouldn't change the BSP filename afterwards or the cubemaps are messed up.

Otherwise very good brushwork and layout.

Looks quality. I might give it a closer look later.

I don't dig the "because we can" attitude towards curved brushwork I see in ff maps so often. Not every wall has to have a curve just for the sake of it. It looks a bit plastic and forced sometimes, taking away the more "stable" look of the original tfc maps. It's a bit overdone.

I think with a different skybox it'd make a huge difference. The day-ish plains are very "meh". Even something of intricate grunge, or something maybe "Fifth-Element" like futuristic but derelect would blend nicely with such nice architecture. I just see it looking nice with a mix of trashy, neon glow/lights and perhaps some stuff floating/suspending in the air to mix in with the smooth, rounded cement.

Man, all I can say is: awesome! This map's architecture is superb! I love the rounded corners and windows. I like the theme too. This map's layout has always worked for a CTF map, and it shines through here. The height variations keep it exciting as well.

You have definitely taken into account detail on all surfaces (especially walls). I like the dome rooms leading to the underwater system; that too was interesting with the green and red lights, (I know those are the colors of the bases, but they worked surprisingly well within the pipes [i.e. It made the fog of the water seem that much more menacing]).

The fronts of the bases are very visually appealing, as well as the shadows cast upon them; that's the image of this map that will burn into people's minds when deciding what level to play.

I don't know why, but I love the idea of being able to see where one just came from in a map. What I mean by this for example: in the flag room, you can look out the window and see the exterior of the dome room just down the hall, and it evokes me to run there. This also helps with guarding the flag, as one person could watch both the flag room and the water exit simultaneously. Great design implementation!

Cons: Very few and nothing really worth meriting another compile, but here they are:

The one drawback that holds this map from its full potential (and most I think would agree with me) is the 3D skybox. It lacks the amount of detail and effort that is so apparent in the map itself. The very few places you do get to spot it, I would think, are worth filling in. You nailed the environment down, but left out the setting, which is the role that your 3D skybox should play within this map.

The bits of displacements you do have out in the 3D skybox don't seem like their sewed together. A-matter-of-fact, I noticed a very obvious fracture in the displacements next to one of the flag rooms. The rest of the displacements just kinda clip into one another, which doesn't look very good (or believable) when you have colliding textures.

One other nit-picky sighting: On one side of the bridge, the very end faces of the green portion of the rails are not textured.

Final Thoughts:
This map looks like it was thought through very thoroughly, and has also been very optimized as well. It is very fine tuned in its architecture, and I would give it a 10/10, but the shortcomings of the 3D skybox are detrimental enough for me to refrain from giving it a perfect score. This is also a very clean map (no gravity gun ammo), which could be a good or bad thing, but I won't take it into account here considering this a CTF mod map.

All-in-all, very, VERY nice design and environment!