needs balancing
this has real potential, but needs to be balanced--ie, the super-towers needed to fight the high-end enemies are too expensive relative to the rewards that those enemies give, making it become impossible to surpass lvl 70-80.
that being said, a lot of potential, and i will definitely play it again should tweaking be done.
btw: cold towers have the best range--from the center, they can hit the entire map.