The pilot is good enough to bring me back for the next episode, but this really really should have been a two hour pilot.
The characters had nearly zero development("But we're family..."), the mechanics(and specifics) of the post-event world needed a lot more exposition. And everything was so rushed that nothing had the weight it should have had.
All that stuff should be ironed out over subsequent episodes, assuming a competent writing and producing staff. The biggest structural problem I see coming is that Charlie and her brother are going to become increasingly useless as this story goes along. They have no particular skills or motivation, or background, or training. They're just kids. And since the show is trying to make them the main characters of the whole piece, it is going to become increasingly frustrating spending time with them when every other character is so much more interesting.