Dwayne Johnson is at the height of earnestness as Davis Okoye, a primatologist in San Diego. It is hammered home that he likes animals more than people, but it is more accurate to say that he likes George, a big albino gorilla that he rescued from poachers. Luckily for us, this duo can talk to each other using sign language (if Johnson is fluent in sign, he should be an interpreter on TV, considering the amount of emoting). This introduces some of the best dialogue in a movie with a super-dorky script.
George is burly, has a bit of a sense of humor, and is in the wrong place at the wrong time when what seems like a small meteor hits the zoo. It is actually a piece of a space station experiment gone wrong that blah blah blah causes genetic modification. In short, George (and a couple other beasts conveniently in the Continental U.S.) begin growing really big, and even more angry.
The movie thunders along a like 30-foot wolf through the woods. The nefarious business moguls that own the genetic technology, a brother-sister duo (Malin Akerman and Jake Lacy, who may as well be twirling a collective mustache), figure out a way to lure the beasts to Chicago. It's kind of fun to see the beasts shaking the Sears Tower until it topples over, but it also leads to a cringe-worthy "somber" scene of shaken, dust-covered bystanders being led away from the rubble.
I could point out that this movie also stars Naomie Harris as the token hot scientist/potential love interest, and Jeffrey Dean Morgan as some sort of rogue government agent who also wants his hands on the ape and friends. (Morgan apparently just changed his costume and dropped his Walking Dead bat, because he phones it in with a familiar slow-drawling, loose-limbed cowboy swagger.)
But humans are an afterthought to the CGI. In fact, the script and the plot are an afterthought to the CGI. It doesn't really make a lot of sense, the only stake at play seems to be whether or not Davis can save George. Never mind that the city of Chicago is in the way of the impending rampage. After all, if downtown Chicago can be 50% evacuated in what seems to be 10 minutes (!), then humans aren't the focus anyway. Just show us giant wolf with wings and a behemoth crocodile Chia pet, and it's we need apparently.