This is some BS. I got all the first four towers fully upgraded and all missions completed and completed the South outside as least four times, within the time limit and kill ratio, but I cannot move on any further!!!! Someone, ANYONE please help!!!!!!!!!!!!
Although you should probably mention that when there is two treasure chests you only need to reach one out of the two. I thought I had to reach both when I first got to level 21 and couldn't figure out how to, so I had to use the walk through and that's where I found that I only had to reach one.