I've tried my best to be as spoiler-free as possible, but this is the kind of movie that is best watched while knowing as little as possible. So if you're wondering about the movie, just watch it now and don't read any reviews including this one until afterwards.
So at first the film is admittedly pretty bad, and I don't think anyone will disagree with that. It's a one-take zombie movie, and I'm fond of one-takes so I thought "cool, a whole movie being done or at least presented in one-take like 1917 but with zombies would be cool I guess." But soon you realise it's not very well made, and there's uncomfortably long scenes and some weird dialogue and poor camera handling. So then you're laughing at how bad it is, and thinking, "OK, there's gotta be a twist if this movie is rated so high" and I guess all I will say about that is: don't go expecting a horror movie; this is definitely more of a comedy. And just have a good time and don't take it seriously. It was a pleasant surprise and elicited a lot of laughs, and further into the movie, the laughs were no longer at the expense of the film (it somehow became genuinely funny, not the so-bad-it's-good kind of funny). So by the end of the film, I thought it was great, despite the rocky start.