I seem to recall that, although the nuclear apocalypse killed most people and animals, there weren't problems with radiation. The initial group of characters survived because they were in a wine cellar, and I think some people who were in parking structures survived. They all went outside afterward and didn't die. There were a lot of fridged family members. I remember not buying the fact that, even if radiation weren't a problem, they didn't starve. What happened was enough that they almost died from the heat of it, even with the protection of the wine cellar.

So I spent a lot of time going, "Wait. What???"