Well nothing much new here. The government makes a zombie gas. Zombie gas gets out. People turn into zombies. Police and their terrorist suspect get caught in zombieville. Along for the ride is a professor (no Mary Anne), a bunch of kids, and a fellow who's been getting ready for the zombie apocalypse for years.
The Serbian location does grant if not anything new at least the illusion of freshness. The acting, writing and make up are all fairly decent. It moves along at a brisk rate and if you like zombie flicks this is better than most.