I've absolutely loved this story so far, and I have no doubt that it took a lot of original thinking and writing to come up with the final story. But I would be willing to bet that at least some of the main writers used the 2004 remake of Dawn of the Dead as a HUGE source of inspiration (besides the fast zombies). Here are a few things I've found they have in common so far.
In DotD, the main character, Ana, gets in a car crash after an escaping civilian tries to steal her car, breaking the highway-side barrier and crashing into a tree. In TWD, Lee is in a car crash that breaks the highway barrier and lands him in a forested area.
In DotD, finding a boat becomes the group's focus and answer for surviving. In TWD, that becomes the mission too after the motor inn falls.
In DotD, CJ is an impulsive redneck-ish guy with a handlebar mustache who, in the roof scene, makes it clear he'll kill anyone to survive. In TWD, Kenny is a Florida redneck who also has a handlebar mustache and is willing to smash Larry's head in to make sure his family survives.
In DotD, there is a foreign (Russian) woman named Luda married to one of the main characters (Andre). In TWD, there is a foreign (Belgian, according to the wiki) woman named Katjaa married to one of the main characters (Kenny).
A lot of people have already guessed episode 5 will end with Lee about to kill himself Michael style, watching the boat sail off with Clementine and the other survivors.
Can you think of any more similarities between the two series? Is there some other non-Walking Dead zombie film you've found significant game parallels to? Let me know.