I know quite a few of us have used some of the same strategies to survive. Mostly sending out one ranger and having the rest man stations.



Personally I try and have at least one room in each direction around the crystal open and powered at all times. This way I have a defensible position and often a node there before I explore the other direction(s) and the big waves start spawning. I also try and make it as painful as possible for the creatures to reach a node and my heroes. Slow module combined with a few Tesla modules is awesome. Get a few of these between spawn areas and your defense room and heroes can kill 'em in moments since the Teslas attack quickly and do decent damage. I also usually have defense boost with massive attack nodes in a node room. The node will cause the rock giants to attack it first, spreading out the damage from the heroes.



Often on Floor 3/4 I'll explore all the way around the crystal room while leaving the crystal door sealed so the waves are more manageable. Monsters will spawn far away from the defensible rooms, and the long route will spread them out due to their slow speeds. At this point I'll also use one or two of my heroes to prevent a room from spawning instead of operating a node.



So, anyone else try anything different?