A lot has already been said about this episode, most of which I agree with. The big thing that stuck out was all the attempts at humor and lightening the mood, including the weird quip from the super stoic Watcher of, "Oof. That happened." Which seemed really out of place for him.
I said to a friend that the non-stop humor felt mandated to keep the show, being animated and probably with the thought kids were watching, from being too dark with dead heroes and people getting eaten, and others dying. I felt like the thought was if they just flood the episode with funny quips and moments and joking that maybe the darker subject matter wouldn't turn people off. To which I say, it kind of ruined what they were going for and I think people could have handled it (and probably made it better).
With that said, this episode was kinda playing around with the timeline of events.
Hank getting zombified rescuing Janet was what set off the outbreak, but that probably happened during or just before Infinity War, but when the Avengers showed up in CA to fight the zombies, Cap and everyone were there, so Civil War hadn't happened yet (so it had to have been before Ant-Man & The Wasp happened). So everyone was already zombified before Infinity War in order for the Black Order to show up and get eaten.
Although Civil War not happening does explain why Spidey never got to join the Avengers.
Then Vision was hanging around treating Wanda in the US, so definitely before he got stabbed in IW, which means he never went to Wakanda to be fixed (especially since the rest of the Avengers were all dead by this point). In that case, why was Thanos in Wakanda with his gauntlet? Besides looking "cool" and being the location people remember him being in the movies, why was he there and zombified at all? And how did he have the time stone if Strange was dead before Civil War?
I know people are saying, it's an episode of zombies eating Marvel superheroes and this is what bothers you?? And kinda, though I do get this is an alternate timeline, but previous episodes did a better job incorporating when things from the movies happened. This just kinda added to the messier storytelling experience because it felt like they just wanted to have more "Oh I remember that scene/place from the movies!" and not actually build a more tangible alt-world with it. A big let down compared to how amazing the previous episode was.
And lastly, I do think the hero zombies using their powers felt weird when normal zombies were the generic dumb shamblers. At least in the comic it was shown they could talk and were sentient, just ravenously and maddeningly overcome with hunger, so it was understandable they could use their powers still. Honestly, I think that route would have made them creepier, because then you could see Cap and Stark were still somewhere in the monsters you saw on screen. Though on second though, that was probably a lot darker than they were willing to go.