Who's left? Finding the small pockets of survivors, and how everyone is coping with the zombie apocalypse. Are there towns untouched?
In the comic, there are pockets of people in many places - most seem to form some sort of community, but... well, something is often "off" about the people they find.
How did it happen? Explore the cause of the zombie outbreak
in the comic, they haven't even sorted that out yet.
Is there a cure? A lot of effort will go into either a cure or an immunization.
So far the one cure is a shot in the head in the comic as well.
What happened in the rest of the world?
Not even touched in the comic yet.
Anyway, I know you are throwing your 2 cents in there and I just wanted to provide a few more comparisons to the comic. No idea how close they are going to stick to the comic, but they have captured the mood/suspense/horror really well so far. Here's hoping it doesn't end up like another heroes (good 1st season, abysmal everything else - imo, of course).