i found some "mistake" or i dont know if this has been made on purpose
at the spawnpoint which is near the waterfall, there is the possibility to walk beneath the waterfall. this means you can enter the area even if it is walled. (as it is not possible to build the walls that near to the waterfall)
so this spawn is quite hard to defend as it can be entered any time.
i have not started from all spawn points but two but apart from that some spawns can not be walled as the textures on the ground just do not allow that. but any attacker can walk over these textures and can enter the spawn ..
as already mentioned i dont know if this has been made on purpose...and if yes...its a nice tactical gambit. i just wanted to state that its quite hard to defend
last not least: the map is really well done! i draw my hat off
keep on posting your maps here!