looks intresting
just some points of observation, your sea colour needs alot of tweaking hehe, at the mo its kinda a odd blue

think of a map that has the same sort of light and water colour settings your looking for, copy its sky.con and water.con files from that map, into your map, then tweak them in the editor. This will save you lots of time twaking them from scratch and also give you a much better finnsih as it also looks like your tree light is default too.
the little island with arty etc if i may so, is kinda too 'nilla style map for me hehe. Really on a map this size you would not need arty anyways so I would totaly get rid of that island.
I like your underground tunnel sysem looks pretty cool, thou the top bit to it does not blend in that well with the "terrain road" as such. may want to work on the textures a little to try and make them match more. Also some of your custom houses look cool, but you can also see they need a little work still with the textures etc.
http://www.vaittinen.net/screenshots/screen007.jpg
if you look there, you can see your terrain flashing though the wall. Now this is the terrain LOD bug, there aint that much you can do to avoid this apart from move your wall a little so the GRID is a little thurther back and you will cut down on how much players see it.
http://www.vaittinen.net/screenshots/screen012.jpg
this little gas bit is abit random IMO, also looks a little bland. might want to take out the gas and mabe make it more into a docks area or factory?
http://www.vaittinen.net/screenshots/screen016.jpg
a foard on a beach is kinda odd to have a road texture underneath it hehe. I would get rid of the whole road bit, and just have a pass that way. as in real life, any tracks that where there from any one driving over it would be washed away
apart from that, nice start
maybe a little small and dont have any lightmaps as of yet but looks cool, looks abit like a muttrah 2
