sorry about the screen shot.
Don't know what happened there

suggestions:
1) make the pit in the center rounder
2) since the map is metallic then maybe make the columns thicker, it will make them look more powerful (right now the grills on the them kill the scenery)
3) use more textures and place them properly in an order
4) make 4 more platforms on the corners in order to scatter the ammo (that will force players to move around to get ammo and get hit less)
5) add reality (try corrupting the walls and floors for example)
6) add details (try making something detailed for the looks, a map isn't only gameplay)
7) fix the lightning, its awful
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8) use lowercase letters on the map's filename
9) lit up the place by placing more holes for sunlight (since default light textures aren't big enough for such place)
10) use another skybox since the map isn't really so evil (just because it has lava doesn't make something evilish right?)
11) try to make the lava flow more real (eg. pipes letting the lava fall in idk)
12) fix the screenshot (you'll need to resize it to the needed dimensions)
13) take some more time to test play the map on servers with other :)

ill go over it when finalizing this map.
thanks for the pointers :D.

very cool layout, but I have a few suggestions...
as razgriz said, you could use more detailing basically everywhere, and the columns should be thicker. Detailing.. put some holes in the floor, mix up some more textures, add some angles/curves and just make the map a bit more visually appealing. otherwise, this map is pretty fun to play with bots. I think you could remove the centre circle, or try to put maybe a floating centrepiece that has the quad on it. and yeah the lighting is pretty weak... try tweaking it a bit.. use more, smaller size lights. And the amo is a little sparce, but that is just personal preference. I think also, you could make the lava pool a bit better, maybe a more interesting shape? or something... i dunno add some angles and like crossbeams or supports... just cus when you fall in it just looks like you forgot to finish the lava pool. Overall, a nice work... awesome layout. 3/5.

add some detailing and change the lighting would make it 4/5.