Survival Mode is a great challenge, though it seems like at some point you are doomed to get fucked by a bad combination of enemy types. Usually I get done in by the zamboni/tractor dudes that are vulnerable to ground spikes combined with the giant ogre types that destroy the spikes with a couples swats. At some point you can't lay down spikes fast enough and the vehicles start to get through and it's the beginning of the end.
The main problem is that it seems like there's never any time to rebuild if your shit gets fucked up, and there are so many enemies that require you to spend Sun Energy just to kill them (balloon dudes, zamboni/tractor)
