Build towers next to the path to defend against the Zombies and Ghosts (left click tower then left click valid location to place).
Build traps on top of houses where Zombies and Ghosts may get past your defenses (left click trap then left click house to place).
Use the gates to redirect the Zombies by opening them up or closing them (left click gate to toggle).
Click the wave bar to call waves early for extra points.
Defeat Zombies and Ghosts quickly to earn more points.
Get more points at the end for each survivor in the neighborhood.