This is a map I have been working on for a few days now, I would really like a bit of constructive criticism on the map because I know it is not good as it could be. I think the map has the potential to be a great map, but I need some help.
As it stands, the map seems very open. I think adding more detail, in the form of large objects/inaccessable structures placed in a lot of the negative space in the map would do a lot for the aesthetics. Also, some of the outlying paths seem very long and rather... bland, if you know what I mean. There are many "bridge and platform" maps out there already, so I would suggest doing something to make it a little more original. A lot can be done there, it just takes a little ingenuity on your part. For me, when I build, I try to get each of my maps to have a gimmick of some sort--something original that forms the core of the map, be it a structure, gametype, or concept. From the pictures, it looks like your big tube in the center is your gimmick. Play off of that--make it more interesting, more playable, more detailed--something special. Then take the concept you've used on the tube and see where you can incorporate similar concepts throughout your map. My apologies for not offering anything concrete, but I always fine it more helpful to offer conceptual advice than specific suggestions, unless I have a really good one. I find stimulating ideas lead to more creative maps in the end, rather than giving exact instructions--because if I tell you exactly what to do, it's no longer a map solely of your design, and I'd hate to force my ideas on someone else's works.
I have added some long covers to the bridge, some braces around the path outside the map, Two cover tunnels on the outside of the map, and some columns on the top mid where the tube is. I still think it seems a little open though, I want it to still look appealing and play well.