For b2:
First, just like many other maps, the problem of being able to build in lava. (In S1)
http://www.hsp.hk/shot0000.jpghttp://www.hsp.hk/shot0001.jpghttp://www.hsp.hk/shot0002.jpgJust simply jump down and build, not much skill required.

. There is no damage to the buildings under the lava. Also there seems to be some graphic glitch as you see in the screenshots.
The general game play problem is humans still rule. The tunnel under the bridge and the "teleporter" let aliens get to the opposite tower. However, it is very difficult to attack the human base since there is only 1-way in basically. You could also consider removing the hole on the second floor of the towers to promote less sniping.
Actually, if not your map has to be related to LOTR, I would suggest "The One Tower". A neutral tower is in the middle and linked to two bridges on both sides which connect the alien and human base. I believe such maps would have less game play problems and promote intense fighting over the tower to establish front base. Well, I just don't know where to set up domination points in your map in the current state :wink:.
I don't have much fps problems in this map.
But really, the best looking map I have ever seen, good work!