I've expressed my discontent with zombie fiction before. So many zombie stories are simply endless sequences of live people shooting dead people in the head. I also think that there are entirely too many zombie video games (although, as a genre, it's certainly outnumbered by "elves, swords, and magic" games, which leads to a whole different conversation).
That being said, The Walking Dead is a fantastic game.
It might be more accurate to call it an interactive story, instead of a game. Though it's a point-and-click adventure game at heart, there are only a few puzzles that could be considered challenging. The quick-time events ("click this hotspot NOW!") present more of an obstacle, but a couple of these are more frustrating than engaging. The rest of your interaction with the story primarily consists of walking the main character through a series of obvious steps.
Once in a while, though, the simple actions you're presented with leave you with a choice of options, and the decision you make has a significant effect on the rest of the story. If you have the hints turned off, it may not even be obvious that you've hit one of those branching points. And once your decision is made, you get to play through the consequences.
The game designers made sure to put some emotional weight behind those choices. There were several occasions where I was horrified at the decision that I was being forced to make, and given only a couple of seconds in which to make it. Those mouse clicks are far more gut-wrenching than any other game's "click here to kill a zombie" mechanics.
Even the sequences where you're just clicking through a series of fixed events are used to really drive home the mood of the story. Whether you're staggering through a corridor or wielding a gory axe, the interactive events put you into the middle of the story and make you feel that the blood is really on your hands.
The art, the writing, and the voice acting are all top-notch. This would have been a decent story even without the interactive elements. But the game gives you enough control to really draw you into the hope and the pain of the characters, and elevates it to a higher level.
I wouldn't say this is a "fun" game. It's certainly not a happy-go-lucky murder simulator where your character deals death with a quip and a wink. Parts of this game hurt to play. But I think this is the best zombie apocalypse story I've seen, and quite possibly it always will be.