Stage 13 cleared. Interesting. There are a few features/bugs. 1, you can cancel out bubbles. Means that when the computer attack with an 100 nano army, I can counter it with a bubble of 1 nano. Also the AI don't attack anymore. They sometimes stay overloaded and do nothing.
Better AI is more fun. Merging bubble is a good idea. You can "eat up" bubble of the computer if you have one big buddle, meaning your armies are added instead of cancelling each other. Cannot do 12 yet.