This game actually kind of depresses me. Giving the cars emotions makes them too relateable as people, and watching them all die out until there is one left or you are alone is pretty sad. Still a great game though :D 5/5
If you do make a sequel (which I think you should) maybe consider adding a level creator, or "ghost routes" - in which you can plot routes through the enemy so when you take a cell it will already have been set to output somewhere else. Along with the other idea's specified by others. It would be a great game, like this one!