I've been playing this for 10 hours or so now.
Impressions so far:
Most of the things you do are really quite boring. Like the barricade, runner in trouble and clear infestation missions are just a pain in the ass when you've done them ten times already. I don't even send out scavengers anymore because they always get in trouble and I hate it when I have to drive into the woods during night and end up touching a stone which will send my car into a backflip and break. Story missions are quite bad as well: they usually only last for a few minutes and many of them consist of nothing more than driving back and fourth across the map.
I think I like the idea of this game more than the game itself. Design wise, I'd say it's not a very good game at all, you really need to put a lot of effort into roleplaying/imagination to fully enjoy it but even that only carries it so far. I get that this is a small/indie/xbl title but that's not an excuse for poor game mechanics(I don't mind the average graphics or the small map though a bigger one would be nice).
When playing this I find that I think more about what it could be and what I wish was possible than that the game actually is fun.
It's not a bad game, I'd give it 6/10 (above average, pretty good).