Create a mock-up of a non-violent shooter game - It should be clear that enemies aren't being killed or wounded.
It can be a side-scrolling shooter, a top-down shooter, first-person shooter, it's up to you.
Examples are Splatoon (shooting coloured ink at opponents) and Super 3-D Noah's Ark (feeding animals).
Canvas Size - Unrestricted.
Colours - Max 32.
Transparency - No.
Animation - Optional.