Arnold is the only good thing in this movie. He's been the Terminator for decades, and he knows exactly how to play it, especially for comic beats.
The story is a goddamn mess. I read somewhere where the screenwriters asked themselves what they liked about the Terminator movies, and they came up with Sarah Connor and Kyle Reese, etc, etc. But they're too busy trying to shoehorn the same narrative into something new and different that they come up with something stupid and silly.
The ticking clock in this movie is especially stupid since it's a damn software clock controlled entirely by Skynet. When it fast-forwarded from 14 hours to 14 minutes, it couldn't just skip ahead to zero in the first place?
I think Emilia Clarke was given nothing to work with, and Jai Courtney is the blandest of white guy actors. He's this movie's Sam Worthington, so bland you wonder who or what he did to get the role. The most interesting thing about him is his name, and it's stupid.