Use left and right arrow keys or ad to move - sideways. Click to fire - the cannonballs will go towards the crosshair. The packages falling from the sky will restore some health. Once you die you can start again by pressing space.
Thanks @Pandakun for your amazing art. When I was stuck I did also use some of your code. If there are any bugs please tell me. Here is the link to @Pandakun's project: https://scratch.mit.edu/projects/306846146 I'm entering this in my school talent show.