To begin with, place 3 gatlings as shown
Now wait for 70$ and build a Tesla tower as shown in next picture.
Dont upgrade it yet.
Build as soon as you get. Pause if needed.
The idea is to increase the path.
Note that we do not have much damage in the long stretch of the path, its not needed.
Get the Tesla and its goo together.
Follow this order.
One level up for Top, then one level up for bottom,
This way upgrade the shown Tesla's to max, one by one.
Keep upgrading the rest, as and when you have money.
One level top, one level bottom. Till you have upgraded all Tesla's to max except the ones at the right half. They are just for safe, if some heli's might escape.
By round 82, all Tesla's should be at max, except right half ones.
Put Tesla's in the order mentioned and then upgrade them to max, in the same way as before.
One level for top, one level for bottom, as and when you have money.
This is almost enough, but still upgrade the right halves in the order mentioned. Upgrade the top one to max first.
After this nothing much to add, just sit back and enjoy ----