It's a horror! It's a comedy! It's a horror comedy!
NASA sent some organisms up into space, and when the ship went to pieces, some pieces came down, and the organism was different. Fortunately, it was contained in time, and stored away, but hey, line items, costs, gotta sell off properties, and the storage unit becomes... a storage unit. And then the alarm goes off that the something special has been released, and minimum wage stooges and retired military figures need to stop the fungus from spreading more.
Basically, this is the common trope of "what if virus got out of hand" with a couple of extra steps in the set up. It's... fine. It's based on a book, and I can't imagine the book is that much more exciting. The horror is mainly around the effects of the fungus on the body, and the comedy is... that no-one is really treating this seriously? Yeah, it's not really going with a lot of jokes, just a light tone.
We have Joe Keery, who isn't exactly escaping the Stranger Things line of being in weird sci-fi things. Liam Neeson is trying to play "gruff military guy" who gets jokes by undercutting things with a tough tone. And Georgina Campbell is also in this movie.
It's just... fine.