Movie critics have a though job, I get it. They have to watch lots of movies and not for pleasure, but as a job. They can't just relax and have fun, they need to sit down and analyze every bit of a movie: script, acting, effects, lighting, music, dialogue, etc. They also have to compare with films of different genres and with the actors and directors previous efforts. There's a lot of work and baggage, and it's understandable when they demand more from a film. On the other hand, this process means they simply don't see films the way the general public does, and this disconnect sometimes means they'll be harsher on a film than they need to be. Sometimes this will be out of handling different expectations, and sometimes, being human as they still are, it'll be out of pure unfairness.
In the case of Venom, it seems to be a combination of both. The film seems to be almost universally reviled by critics while almost universally loved by audiences. While being completely fair I'll admit many of the complaints about this movie are completely legitimate, I still believe the treatment is receiving by critics is still preposterously exaggerated. I've ranted about this before, but it seems critics have simply grown accustomed to the Marvel Cinematic Universe's formula, and anything that strays from it in any direction is automatically judged harsher, whether it deserves it or not. And Venom absolutely doesn't. Yes, it's campy. Yes, it doesn't take itself too seriously. Yes, it doesn't have any messages and it doesn't deal with any current socio-political issues. What does Venom offer in place of all that? Simple, primal and unbridled FUN.
Venom is the story of Eddie Brock, a reporter who believes in doing the right thing, even by using unconventional methods, and even if it means telling the truth about powerful people. Is because of this that he decides to investigate on a rich industrialist who's secretly kidnapping people and experimenting on them. This gets him in serious trouble, and having no good deed going unpunished, he loses his job, girlfriend and apartment. But when a scientist grows a conscience and tells Brock about the secret experiments the industrialist is doing by merging humans with parasitical sentient goo life form known as "symbiotes", he decides to pay a visit and inadvertently becomes host for one of these creatures. Hilarity ensues.
The symbiote merging with Eddie calls himself "Venom". It's an intelligent creature that needs to feed and has less scruples about killing than Eddie does. With Eddie they form a symbiosis: the alien will augment Eddie's strength, agility and resilience while Eddie provides the alien with sustenance until he can find his companions. Having no choice, since he's being followed by people who want him dead, Eddie complies, but now finds himself bond to a creature that could cause the deaths of millions. Meanwhile, another symbiote named "Riot" is traveling the planet in search for the rest, and he has even less respect for other forms of life. Will Eddie be able to control Venom or convince him to join his side or will Venom and Riot unite against humanity?
Here's why Venom resonates so much with audiences: the story is simple to follow, the main characters are likable and, unlike other films in recent years, it doesn't try to beat messages into the audience's heads. Expect no attempts at political agendas or social issues; every bit of dialogue is in service of the story or the characters. But the main reason is that both main characters are just really fun to watch. Eddie and Venom form basically a buddy cop movie, with two different personalities clashing and being forced to work together.
They're also bloody hilarious. I complain a lot about movies in the MCU using humor as an excuse for plot development, having every character being a snide wise-cracker and ruining legitimately tense moments for the sake of a joke, but this one doesn't fall into those pits. The humor is relegated to Eddie and Venom's relationship, so not all characters feel the same, and tense moments are not punctuated by jokes, so the tension isn't lost.
Yes, I'll say that there are a bunch of plot holes and perhaps the story is too overly simplistic for those who expect something more, but if you're willing to just relax and have fun, this movie does the job very well.
How does it work as an adaptation? People complained a lot about the movie not being R-Rated and Spider-Man not forming part of the origin story, an I say that those people simply have no idea what they're talking about. Venom has always been goofy in the comics, this isn't a new development, and Spider-Man's involvement is unnecessary, since the character is strong enough to thrive on its own. Yes, having Venom show up in a Spider-Man movie would be benefitial... for Spider-Man's character. But Venom can perfectly work on its own without Spidey. That being said, I would very much like to see the characters clash in the future. We'll have to see, since it's still not clear if Venom and Spider-Man even exist in the same universe yet.
Bottom-line: if you're expecting elaborate plots, social messages and/or a serious tone this is the wrong place. But if all you want is fun, Venom will do the job perfectly.