the final level is impossible. it was demonstrated by someone who modified the game and had a full board of dca turrets fully upgraded and still could not beat a wave of air units. i forget which wave or where i saw this, it was a while ago. but, it is fact.
uh, i finished the second to last level and halfway through it wouldnt let me skip and after i finished the last wave, it got stuck. i just wasted SO MUCH TIME! D:<
an enemy went straight down off the screen and now i am stuck on the last wave and cant fight. i couldnt click attack after it happened either. i just finished a long level too.
click and hold the left then the right button on the mouse to keep the speed up mode on. it will release when you click again. up vote this so people see it.