This is a zombie flick, the most worn-out of genres, by Zack Snyder, the most worn-out edgelord filmmaker of the millennium. And it's vastly, vastly better than I would expect.
The title credits show the rise and fall of Las Vegas zombies with Elvis singing, you think "oh that character's totally surviving"… no mercy. Over the top but not quite into comedy range, tho I did laugh at some of the machine gun scenes.
So now years later, Vegas is walled off, the few surviving heroes are in dead-end jobs, or refugee camps. A fixer (Hiroyuki Sanada) hires ex-hero/fry cook Dave Bautista to gather a heist team to extract wealth from Vegas before the inevitable military solution.
The team's full of fun character actors, from Garrett Dillahunt (Francis from Deadwood, Ty from Justified) as the Carter Burke company man type, to Ella Purnell, one of the girls from Miss Peregrine's. And a lot of the crew are stunt performers. Samantha Win does a great job channelling Vasquez from Aliens, right down to the red bandana, tho there's no Lieutenant Gorman analogue in this.
The gunfights, knife fights, and brawls are quick and bloody, nice honest squibs it looks like in most shots, with a few cartoony but generally blurred-out CGI shots for machine-gun fire melting armies of the dead.
The crawler zombies are slow, dumb, and follow Night of the Living Dead tradition of just being extras in makeup, not too much effort. The ghouls, or "alpha zombies" as they call them, are heavily made up and sometimes CGI'd, especially their bright yellow eyes. There's some interesting zombie ecology/culture built up here, especially Valentine, and the showgirl, and Zeus.
I make a lot of comparisons to Aliens, because this is clearly like 50% Aliens + 25% original Dawn of the Dead + 25% Zack's Dawn of the Dead. Which is fine, Snyder needs a better template than just "dark superheroes brood and kill people", and here he's got one. This is shockingly superior to anything Zack's done since… Sucker Punch?
There's a spinoff TV series already in production, it seems, covering the zombie war, I'm definitely watching that.