>>32590115Dr Brainiac is the only intelligent zombie because he was super smart when he was alive. He targets your neighbourhood (Your house is the only one left) for your brains but you have plants to defend against his zombie army and machines (small suburb in america is a good target because reasons). Later games start to up the ante, giving both sides better tech. The plant side gets sun-energy powered nukes, the zombies get teleportation tech and mech suits. Both sides are now eternally competing in an arms race to destroy the other side's leader. It is presumed that in-order to run the war, Dr Braniac is artificially growing humans and then turning them into specialised zombies which is why we see so few types in future games and why things like super-zombies become possible. The plants (with the help of crazy dave) start to evolve and get much of the tech stuff but through biological means. The eventual conclusion of the game is that without Braniac the zombies are toast, but the plants can survive without crazy dave so they win.
A very simple plot really.
