Allright, very very nice map, with lots of love into designing it. I really get the feeling of a deathmatch map here. However there is a few comments i'd like to make on this.

1. The sun. If you already have a skybox with a sun, check that the shadows of the sunlight point in the right direction ;)

2. Dark spaces. There's a lot of dark spaces inside. It makes the map appear unfinished or sort of plain.

3. CTF will be very bad on this map. There's lots of ways to get to the flag once your inside the castle, however only one way to get into the castle... There should be at least 2 possibilities to get into the two castles.

4. Symmetry. Both castles are symmetrical. Use a sign to at least tell them appart. Perhaps with a bowl of blue fire and a bowl of red fire or something...

5. Open space / close space. The first rule on mapping is to not have to many open and not to many closed spaces. The problem i see is that when your midfield your on open space, hell you even made sniper towers xD and when your inside the castles the space is very tight, eg. stairs etc. Dont get me wrong, I love the level design, but playability will not be so great.

Perhaps you want to make another entrance possibility to the castles. merge some rooms, widen the doors for more jumping possibilities. You might also wanna put some more items in the middle for doding those snipers on the towers ;)

I'll give you a 3 (5 for leveldesign, 2 for playability)

Well its maybe just not my taste but i would delete the glass from the windows.. its meant to be defended.

try to fill the main area with something else then random crates!

way tooo small doors in the castles.. youre meant to jump and run. Sauerbraten needs uber sized doors cause of the fast gameplay.

but well i would give it a 3 too

I agree.. The glass tex should usually be avoided.. Well not usually, always. I would remove them to leave the building open. That would make it more natural and as an added bonus you've just made more paths for people to get out of the building through.

The castle interior needs to be reworked I think.. There's a lot going wrong there. First off, they're completely symmetrical. There are two spiral staircases, two hallways with random rooms, and one huge open room in the middle. The castle doesn't feel natural or genuine at all. I would suggest removing at least one of the spiral staircases.
The other thing in the castles is that you've not done anything for noclip. The trimming for the windows, doorways, and other parts all needs to be done. Also the torches are still solid.

Furthermore about clipping, the clip boundaries you made on the boundary walls isn't everywhere. There are noticeable holes. Sometimes when you copy a selection the clip won't be part of the paste. So put that in manually I guess.. Also make a clip ceiling to ensure nobody can stand on the clip.

The sniper towers may be a bit much. After all, once you open up the windows that will change the strategy completely. Maybe make them useful for sniping instead, and then you can just remove those annoying spiral staircase towers.

Finally, consider adding trees, fountains, SOMETHING to make the open areas not so open.

But you've got a good setup here. The details are rather great most everywhere. The lighting's a little oversaturated in some parts, and not enough in others. The insides, for example, need sprucing up. I think this would make a good map for CTF to be honest. I'd have to look at it a bit more but it has the fundamentals down. As for DM I don't know. Symmetrical DM maps are fundamentally flawed. Speaking of, yes.. Ensure that each side is clearly indicated. Otherwise people will just run in circles if they haven't decided to depend on their compass.

4/5.. I really like this but you have quite a bit of work yet to make this feasible.

not very original idea, but k...
the lightning can be done better (lightprecision 10, why not like 16 at min. but i suggest 24) (ambient hasnt been used, that makes lightprecision doesnt work that effective, maybe u should take ambient 18). the basic light could be less yellow, exept if u would replace the grass texture (hard 2 c that its a grasstexture because of the light) for sand or stonetextures.

geometry isnt bad, but could be improved a bit to.

i agree with misan that the doorways should be much bigger. with those small doorway u promote camping in the castle 2, what decreases the gameplay.
maybe an idea, but it could be nice if u would mark with signs in the castle if ur close 2 the enemy flag, or far away from it (because its like a maze, what decreases the gameplay to).
i c u trimmed the doorway very well but u didnt trimmed anything on the ground further, what takes the effect of the doorways away. maybe a suggestion to trim further.

the gameplay, is actually incredible worse (srry but cant put it different =s) because its all focussed on camping, while it should be on capture the flag (thats why, try to make cover for the people who are running from 1 castle to the other, and delete those camptowers).
further, maybe a suggestion but u could remove the small jumppads connected 2 the grassfield and replace them for stairs to make it harder to camp on.
im sure some1 will come once with the idea to make some kinda sewer into the map, plz dont, it wont improve the gameplay.
those boxes arent bad, but plz just make it less symetrical and more random.

anyways, u seems to have a lot to improve on the map :P. keep it up and edit like hell :P. ill give 45 points for now.

p.s. maybe u get some idea about gameplay on this page that i got from meatrome (still thx meatrome :D):
http://book.hourences.com/bookgameplay.htm