(Stuck) Inside Comet - can't leave the village/inner circle

Hi there, Love this game, but I'm stuck. I'd really appreciate it if someone would help :) It's probably something simple, that I'm missing, since nobody else seems to have had this problem. I can't figure out how to break through to any of the paths outside the "inner circle" inside the comet. I'm guesing that I need to destroy the purple crystal towers/columns that are blocking the exits, but I simply can't figure out how to do it. I have built and upgraded everything available, and tried every weapon, tower, skill and sneaky idea I could think of, but nothing works. I built towers around the edges of the inner circle, so I can see that the paths are there, though I can't get to them. How do I break them down so I can move on? :confused: I searched this forum, read several walkthroughs and watched gameplay videos, but found nothing about this. Thank you :) /Flo

A lot of gamer getting stuck on this part. I would say that this is one of the challenging scenario of the game.

There is place which looks like it's a bit invisible you can take your tribesmen under it.