1) Your assets weren't packed properly, so everything was kind of blinding and purple and ERROR. That should be easily fixed, though.
2) Did you have cubemaps? The water was suspiciously purple. (That's also easy to fix.)
3) The ramps going through the center area were really awkward - you could get onto them from the side, but it was a really fiddly jump. Either push them back, so that you can just walk onto them from the center, or put in a wall, so that it's not an issue.
4) The map as a whole felt kinda small. There were a number of places (like the ramps and those little L-tunnels) where there was no place to slip by, and the map as a whole was very linear - everyone had to squeeze through that watery bit with the trees. (Brief aside: someone else suggested playerclipping the roots so players wouldn't bounce into the air after touching them.) With the flags directly past the spawn (I'm guessing; I never got close enough to get a good look), everything stalled.
So add a few alternate routes and widen things generally.
Anyway, luck with the map and keep it up!