This might be my crappy luck, or it might be a programming flaw, but my squares ALWAYS go off-screen and my triangles ALMOST ALWAYS shoot the one dark shape on screen, especially if it's my first click.
I'm making money right now on courier missions- low risk, lots of cash- and so, what I've begun doing is putting it on autopilot and going to another window where I watch youtube videos. When I hear shooting, I switch back and take care of it, then return to my vids. Just sharing a useful tip.