Operation is simple only jump by tapping.
Jumping and fending off obstacle let`s roll earnestly!
You are the snowballs that becomes larger and faster if go in deep snow.
Conversely that becomes smaller and slower if hit the rock.
But perhaps it might help you.
However when hit the rock when too small ... it will be broken!
Do it larger or smaller up to you!
In strategy and reflexes and courage please rolling around everywhere to!!