I'm level 25 now, I;ve got the glowing borders on the first 6 areas (revealing the first secret level) and have completed up to and including the first epic battle.
When I started playing the game everything was fine but the last dozen or so battles that I have played when I'm finished the screen goes dark and I can see trees and towers, then it goes back to the main screen which is also black except for all the areas show up. When I try to save the whole screen is black but if I click in the right areas I am able to save.
I have been reloading the webpage (and therefor the game) and relying on the autosave slot to continue playing - sort of annoying - anybody else have this problem?