You don't have to watch the show to enjoy the game at all. It's not that the atmosphere or the story of the game is the problem (even though it's nothing special, and watching the show doesn't help much), but the gameplay itself is lackluster. You just run around shooting bandits, mutants and monsters in the open world which is either countryside or later on an urban area, with very few instanced indoor missions. So the landscape doesn't change much, and the way you play doesn't change practicalyl at all since there are very few active abilities you get during leveling. Specifically, there are only four of them, and you start with one. Everything else are various passive modifiers which either boost one of those abilities or give you stuff like +x damage with snipers or when attacking an opponent from behind. So although it's decently fun, it's the same old, same old all the time. It gets boring rather quickly for an MMO, and since there's no point in rolling alts... This is actually the only MMO which I've played for less than a month I think. So yeah, move along, nothing to see here.
And oh, tying the game to the show - it has no effect on anything. The game was released and the show started in April, and the first series of the show concluded in July. The next season is scheduled for June. Since the game and show are running concurrently only four months a year, you can't really have stuff from the show carrying over into the game in a manner that feels like one is affecting the other. Instead, if you watch the show, you'll be familiar with the setting and characters in the game, and that's about it. So it's just a fancy novelty with no practical ramifications whatsoever. No difference from making a game based on any other already existing property.