Overalll, I enjoyed it. But I gave it a B- because I feel like the script could have used a bit more polish, and leaves too many important details unclarified that would have helped the narrative. It seems a tad odd that Olivia Wilde isn't properly credited for her shared role of Gozer (she plays the solid physical form, while Emma Portner plays the CGI spirit form and Shohreh Aghdashloo provides the voice).
The Good Stuff:
Visually, the effects are pretty good and a nice nod to the originals. I liked that the story got more into the past of the Shandor cult and provided some background for the Shandor Building in New York. McKenzie Grace did a nice job as Phoebe Spengler and it was fun to watch her interact with Egon's ghost at times.
It's kind of nice also that Ecto-1 has a roller trap, although that also creates some annoying confusion (see below).
The Not as Good Stuff:
As I said above, there are areas of the story that really needed more detail. A lot of reviewers and fans have been uncomfortable with the portrayal of Egon running off alone to Oklahoma, and Callie's constant inferences that he was a shitty family member. And while I do think Egon was always an eccentric nerd, that doesn't seem to fit his character. It would seem especially strange for him to act that way in the context of the second movie, with Peter strengthening his relationship with Dana and wanting to protect Oscar.
I also feel like both Callie and Gary could have used a bit more fleshing out, in terms of their personalities. Carrie Coon and Paul Rudd are both good actors, but it feels like the characters are used more to advance plot points at times than feeling natural. Callie is never given much personal detail as far as her interests or job skills, because her main driving force for most of the film is her estrangement from Egon. Gary is rather conveniently a seismologist because it works for the story, but it would be nice to have a line or two where he explains that he stayed in Summerville because of the odd phenomena.
I think it was a mistake to imply that the Ghostbusters just sort of disbanded and were largely forgotten, because it just doesn't make logical sense. When GB2 was being developed, Harold Ramis came up with the idea that the team had to deal with some fallout after defeating Gozer and would have to build themselves up again. And it's not a bad concept, but it's not executed very well for that film. It's more like the majority of New Yorkers just conveniently forgot or were connived the Ghostbusters were a hoax.
Ray tells Phoebe that the spirit business sort of "dried up" and ultimately led the business to fall apart, with the exception of Egon and his studies of the Gozer cult. But I feel like the concept of him disappearing and being thought of as a weird crank in the middle of nowhere could have been worked out better. It's also kind of jarring that Podcast had never found anything on YouTube about the 1984 events before Gary described them, when YT seems to have plenty of information on those events. It's just the sort of thing he would already love.
There's a bit of confusion and a plot hole or two regarding the ghost traps, albeit kind of minor. It seems like the kids have two main traps essentially: the one that Egon used at the beginning to trap one of the terror dogs (maybe Zuul?), and the roller trap they find in Ecto-1.
This leads into some weird and arguably silly stuff with the plot, as there'e no logical reason for Gary to open the trap at all. He seems to be the only one who knows about the Ghostbusters and at least a basic idea of how their equipment is meant to work. And he knows the trap is full, so why open it? At first I thought it was meant to free the trap so Phoebe could use it on Muncher, but they wind up using the roller trap anyway.
Later on, Podcast uses the roller trap to capture Zuul and free Callie from its control, and the trap is stored aboard Ecto-1. But when Phoebe lures Gozer into the field, with the normal trap (like Egon does at the beginning), Zuul is somehow inside that trap when Gozer destroys it. Maybe the intent was that the roller trap is modular and the wheels are bolt-on, but I can't recall it ever being shown that way in the movie. It seems to be a separate unit designed specifically for Ecto-1.
It's a bit strange that even though Summerville is meant to be the isolated town archetype in the middle of nowhere (which doesn't really exist generally outside of Hollywood
), there are times when it seems to be strangely devoid of people even for such an obscure place. It's particularly weird during the Wal-Mart chase, as the Wal-Mart is literally empty except for Gary. It would have been better if it were more normally crowded, since there's plenty of potential for Vince and the mini-Stay Pufts to scare other patrons.
I have to say, the mini-Stay Pufts are the only element I could have done without. They didn't serve any useful story role and they seemed to show up randomly for plot requirements, even within the first few minutes of the Wal-Mart sequence. They just randomly appear in various sections of the store where there likely aren't any marshmallows to possess, so does this mean some of them are just random ghosts that
look like Stay Pufts?
I had a good time with Afterlife, even it it's not perfect. But it could be worse.
I just wish some plot elements had gotten a bit more polish and foundation personally.
They'd done such an incredible job with the license over the years - tying all the various versions of the GBs into a multiverse, crossovers with TMNT and Transformers as well as said other teams, even going some way toward redeeming the Answer The Call group. Their last effort, 'Year One,' was clearly setting up Afterlife at the end as the movie was supposed to debut right after it in May 2020, but then... well, we all know what then. 
They couldn't put out any more stories following up from a movie that hadn't happened yet, so I guess there was no choice. *@$^(&!@#% COVID...
