Hey after level 30 it's nearly impossible to win. The game straight up does not play the same rules you are. Also I found out how to cheat: Make sure you have full energy. Then lock the device, unlock and quickly spawn tank, grenadier etc. All sprites curently on screen will be frozen and cpu will not spawn new ones, you can just walk in. You will not be able to regain energy anymore after this, so you will need to restart the game.