Either that or I imagined it.
Judging from the trailer though it does seem serious in a strange way. If you were confronted by a dangerous creature you wanted out of the house you would initially panic, that's fair to say. For example see the bit after the news report where the guy in the tux with only one arm wanders into the house, the two guys on the sofa damned near crap themselves but once they realise that the zombies can only manage a very very slow stumble they realise that they have time to experiment with weapons (though records would seem a poor choice in any case).
In a lot of ways, the scenes in the trailer sort of gave me the impression that the characters are reacting to what has happened in quite a practical manner. Jokes and little screams aside.