Have to say that it was watchable, but overall I was a bit under-whelmed by the whole thing.
One major issue for me was the casting/characterisation. I just didn't really connect with the characters. Without any connection, it makes it difficult to empathise with them and their story, which makes the whole thing more of a chore than anything else.
The only one I had any sort of connection with was the boy/son, who in many ways was actually setup as the least likeable character, go figure.
The daughter came across as just spoilt, 'oh deary me, I'm so darned clever, what am I going to do!'. How about get eaten and put us out of our misery.
The mother just seemed to need a good slap round the face, don't really know why, just how I felt about her.
The father/step-father, well, he was just one of those distracting characters, one of those faces, you know you've seen him in other movies or tv shows, but you can't quite remember what, and don't know his name, and actually you know what, I don't really care anymore.
Maybe they'll grow on me more as it gets going, but it's not a promising start.
The other thing I didn't quite get was what is the point of the show. It was advertised as a prequel to the original, dealing with how everything started, but one episode in, and there are already zombies ... not as many as in the original (yet), but there are already zombies, so it hasn't really gone all that far back to before it all happened, so doesn't seem destined to fill much of the back story in.
So not really blown away yet, but it is only episode one, so I'm prepared to hang in there and give it a chance to improve and draw me in. I believe there are only 6 episodes in this first series, really short for a US show, so it's really only setting the scene and introducing the characters, I'd guess by series 2 it will really just be a fully fledged Walking Dead version 2, zombies everywhere, blah blah blah.
I should say that even with the shortcomings, it's still more watchable than 95% of the crud on offer here, so don't be put off giving it a viewing by my criticisms. It does have a lot to live up to compared to the original, so no surprise if it's a bit of a slow burner