My 4-year old son was afraid of ants. He would scream every time an ant crosses his path, no matter how tiny it is. I thought why don't I create virtual ants, let him squeezes it and kill his phobia. He felt bored shortly after that.
I thought if I could bring in something interesting, it might attracts and retains his attention. It did but I felt bored... I pondered for a while to get myself interested. You need some challenges. So there came the Ice for freezing and halting the ants, and the bomb to help you kill all the ants. And there are obstacles (in terms of trashes) that obstruct you from kill the ants. If 3 tiny ants get away from you, there is it - Game Over!
And to add more challenges and fun to it, the ants will drop thumb pins that will prick you and kill you instantly.
That's how the story and the gameplay are formed. It is simple enough for casual play yet challenging enough to keep retain.
I hope to have your support so that I will have more motivation to work on future titles.
A video of the gameplay here.
Thank you for your time.