Damn, I wonder how people are getting such high scores. After round 70 or so, it becomes incredibly difficult to kill those enemies even with second upgrades. Maybe you have to upgrade to level 3 by then, but how to get enough gold then?
If you see the video released by them on the first round strategy adopted it doesn't require to have level 3 weapons at all squares it just requires a combination and the understanding of working of the weapons on each level I have tried my best on the round 2 but I couldn't move past the 800k score