Basic verdict: good, once you get past the fairly obvious gaping plot hole AND the fact that the pto-PRC agitprop is only mildly subtle (I personally think that it’s cute the way that the ChicComs think that we’re going to deal with societal problems the same way that they do; eg, badly). But dear God but it was grim.
But it was grim that tried to take the concept of time travel seriously, so go ahead if you like the genre.
PS: Saw the trailer for Red Dawn. Still has an incredibly stupid premise, sorry.