I dunno. The Walking Dead is an Adventure Game, in the same vein as Monkey Island, or Sword and Sworcery. Adventure games have also been known as "point-and-click" games in the past, too. I don't think it makes it any less a game than Halo, for example.
That said, they are quite different in how they portray their story. In Halo, you have more or less a sandbox shooter, where a lot of the story is discussed through cutscenes, like a movie; whereas, in the Walking Dead, most of it is shown through dialogue and interaction with other characters, despite the game being much smaller in scope, you still have a meaningful experience. It's just different.
I think this is the downside of labelling them all as "Video Games" under a catch all phrase. There are way too many different sub-genres, RPGs, Adventure, TPS, MOBA, FPS, MMORPG/FPS/whatever, Rhythm, Puzzle, Fighting, etc. And even meta-genres like Casual (Online, or Mobile) vs Core (PC, and Console), but even those don't follow strict lines, either, since the Walking Dead is available on all those platforms, and Halo, only on one.
It's like comparing (the new trilogy) Star Wars to 2001: A Space Odyssey. Except that even those are more similar than these two video games.
/nopointtobemadejustrambling