Currently there is a lot to do. I try find the top priorities.
The background color is too bright and yellow, when u r at game, bg is blinding ur eyes and then u can't see ur bullets.
Other thing is polybugs. They are everywhere. To fix that, at first you need to decrease number of polygons (the ones where players can walk), at second you need to overlap the poygons, take a look at 5th picture of this tutorial
http://forums.soldat.pl/index.php?topic=29244.0The map is very small and tunnelish. That means 2on2 is maximum. At 2on2 map works pretty fine.
Again as a tip I recommend u to swich ur soldat mapmaker to soldat polyworks.