The walls in the new mode will actually just be a flood of dogs. At the edges of the play area they stack and create a wall. Outside of that the city is just flooded with dogs up to the top of the wall. That is how damage will be dealt if you're outside the play area. When an area closes in, you see a tidal wave of dogs flowing in from down the street. All of their barking slowly turns into an ear bursting roar as the play area closes in.
Are you intoxicated