Ok in the demo all i saw was water, water, bottom, hint/func_walls, water,awkward skinny hallways, water, water, bottom spawn.
I have no idea how you would make it less awkward and stuff to get out of bottom.
Ill have another play around with the hint brushes and stuff.
and I dont think theres a better alternitive to the skinny hallways.
Sorry for double posting. back to work on it.
