Those 2 publishers publish the same game, just in different regions.
But yes there are 2 Walking Dead games. One by Kosmos/Cryptos, and the other by Z-Man Games.
One big difference is that the Z-Man Games one is not recommended for less than 3 players, whereas the Crypto/Kosmos one is recommend with 2 players also (which for many people is a dealbreaker. I refuse to buy games that don't play with 2).
You should definitely watch some playthrough videos or video reviews to get an idea of how the games play. Don't pay too much attention to the individual reviewer's opinions as it is just the view of one person, but use the videos as a way to see how the games play.
The Z-Man game is Tough! 2-3 players will likely all lose. It is also based completely on the Comics. Not a bad game, just tough to survive.
It's been awhile since I played it but that is not my recollection... Maybe a better way of putting it is it can be difficult, but you will potentially reach a tipping point after which it becomes impossible to lose. There is a very good chance you'll end up dying early in the game. However as you explore more and get more followers you are eventually rolling so many dice (unless I missed a rule somewhere) that you can't lose. At that point the game becomes trivial. I should also mention this is just based on my recollection of solo plays. There are some other dynamics that come into the game w/ other players. Overall it is not a bad game, and I may eventually get the follow Prison game as well. However, it is not usually the first zombie game I pull off the shelf though
Unless you absolutely have to have a Walking Dead themed game, wait for Dawn of the Zeds (Third edition). I know as a new user here I shouldn't point out ratings too much, but both games are under 6, and I have already seen one of them, if not both, hit clearance locally. Yes, I'm aware it won't be released until early next year, but it will be the game that will stick around in terms of getting played far longer. You have vikings in your name, go grab something like Champions of Midgard or Blood Rage while you wait.
Ok, another point: The Crypto one uses the characters from the tv show. The Zman one uses characters from the comic. Theyre the same characters of course but in the comic artwork they look different. So Rick in the crypto version looks like Rick on tv but in the Zman version he is the guy in the comics.