Sadly it becomes to easy as soon as you discover the power of the Frost tower.
Buy one of these, place it centrally, Max Frost tower upgrade, and expand range to cover to the whole map and then work on gettin reload down. If you do you'll be unbeatable until it's maxed and then you'll have plenty of cash for more towers.
Yep, The level was fixed after walkthrough has been done, but it's easy level, so we decided not to change the video