Season 5 is this show's only bad season. Two-thirds of the FINAL movie is generic and forgettable, but it ends strongly enough to rescue everything. Overall... it's okay. I don't dislike it. A memorable ending can make up for a lot.
Our heroes have found their way to a colony called Utopia. Inevitably, it doesn't live up to its name.
1. It has a privileged upper class who live in elegant luxury and have mad scientists trying to invent a zombie virus vaccine. Yeah, I remember that. We did the mad scientist vaccine thing in Season 1 and it worked better then. The show's going back to basics, but all the ingredients are sub-par. (a) There's no significant zombie presence. We hardly meet any undead these days, although putrefaction means those we do see are dog-ugly. (b) The mad scientist is a pipsqueak. (c) The old bastard pulling the strings isn't scary either, even though theoretically he should have been given how hard he is to kill and how much damage he does to our heroes. In fairness, though, the vaccine guinea pigs are horrible (and it's amazing to think that our mad scientist looked at them and thought he was on the right track).
2. It has an undercity where the lower class lives in squalor and filth. That place is scary. They have a corpse pit, for instance, into which ruffians push people they don't like.
3. It has a Resistance, because of which the privileged class will shoot many people in the head. They do this to kill the Resistance, or to learn information about the Resistance, or else perhaps some poor sucker got caught up in a general panic and what the hell.
Season 5 doesn't star the main heroes of Seasons 1-4, although it's not completely without familiar faces. I was delighted to see the brief return of my favourite character in this show. (Her role is small and dour, though, including a Brave Tough Sad Speech.) Season 5's focal point, unfortunately, is a character I called "IDIOT". She caused Season 4 and she's just as dim here. Her response to the body count is gormlessness and a face like a slapped fish. She believes in equality and dislikes killing. I want to approve, but the way she voices her opinions would make even Mother Teresa want to kill someone. This is heading for a finale in which IDIOT has to shoot her ally in the head as a demonstration of... look, I don't care. That was stupid too. The people cheering her are worthless. The victim didn't deserve it. The society where she's finally established herself doesn't deserve to survive. Presumably that's the point of the story, but she and they can still bog off.
Season 5 does have memorable bits, though. I was amused by the privileged heir who throws his weight around and assumes he's superior until his dad proves unexpectedly ruthless. Hah hah hah.
FINAL brings back the show's main hero and is emphatically the end. It's also interleaved with "twenty years later" Mad Max scenes, when everyone wears desert survival gear and you'll wonder if civilisation has survived. Our hero's slightly less scary and unbalanced than he was last time, but he's still looking for his daughter. Don't get in his way. The things he'll do to get her back... whew. One choice in particular is terrifying. The baddies are bland and the zombie action's negligible, but the shocking last act is willing to kill surprising people (three times!). Finally, the Mad Max desert people say goodbye. That was powerful.
Despite stumbling in its final season, this has been a pretty good series. It's been zombie-light, except at the beginning, but it's a strong examination of what people can become as the world collapses and the nearest we have to currency is tinned food. Tough guys discard all restraints and become terrifying. Or, to put it another way, stupid. When zombies are trying to eat everyone, you'd think the last thing we'd do would be to start murdering each other, but ahahahaha. Throats will be slit and brains blown out... but there's also always been hope. That's true here too.