Check out this extended trailer for season two courtesy of Darkhorizons.com http://www.darkhorizons.com/news/21468/extended-walking-dead-season-two-promo
That sounds like a job for the Mythbusters to be sure. I would believe the concussive wave from the grenade would pack more wallop than the shotgun, no?
I am looking forward to Bear McCreary's (Battlestar Galactica, Caprica) score for this show. The Walking Dead had a pretty good presence at Comic-Con this year. A replica of one of the sets was created for fans to have their photo's taken.