I must be missing something, I'm sorry. Is this intended to be a persistent world? How many players? What am I missing?
PBBG - persistant browser based game. Effectively an "MMORPG" for around ~100 players played in browser with very little graphics.
Are barricades permanent, or do they get broken down by zombies over time?
Semi-permanent. They last for a long time until some catastrophic event that rarely happens (someone setting off a bomb etc) destroys them.