The ending kinda shot the movie in the foot. Nothing was really explained. We just got to see how a few people coped with a natural catastrophe. But the lack of actual wrap-up left me quite dissatisfied. (How much of the world was affected? Preteens will run the countryplanet now? Iirc they said third of Paris's adult population has died, but it seemed more like 99%. Why didn't the wind disperse the fog for days?)
Another weird thing was the dog that chased them through the city. Ok, let's say it's young enough that it's not affected by the gas. But still... family dogs don't behave like that, practically hunting down people over long distances. It wasn't protecting its territory, it wasn't starved, it had no reason to behave in such an unnatural way other than plot convenience.
Also it was weird that they didn't just get in a car and get the f--k out of there. Even if the roads were blocked by other cars there must have been smaller streets and such that they could have used to get around.
Aside of the above plot malfunctions, the atmosphere (haha) and emotional tension worked really well, and the visuals were pretty good. The child actress was mostly terrible, but sadly child actors usually are.
Review by kazerniel from the Internet Movie Database.