if you're finding it hard to maintain power on "The Mount", note that Reactors are effective no matter how much space is free around them, unless there's enough space for a collector to work better.
man, the final enemy was weak. seriously, evne whtie weakness on one summon couldn't help much.
I did have to do the occasional healing for my support characters.
DO NOT use massed flamethrowers. burning zombies create smog, which makes other zombies stronger. so, don't use flaemthrowers, PERIOD. guns are better, really.