i highly recommend having an entity briefly flash when it's shot - that's the easiest way i've found to ensure the player understands if what they're doing is working.
Yeah, after I typed my reply I had that realization. It's as if I forgot how to video game. I added a flash and on the red cars there is a chance for the car to "shimmy' which resets the AI ( i.e. The gunman goes back in the window). Haven't uploaded any of the changes yet. Had a few bugs (like shields not working as intended and getting stuck in the walls) that I also fixed. Have a couple more small changes to make and will hopefully release another public build tomorrow. Thanks again for the feedback!