I don't want to spoil the film too much so I am being careful with what I say, especially as I really enjoyed the film and do recommend people watch it.
The Good
If you like big action and big sci fi, then this is the film for you. Yes the story is a bit cliché at times, but does that really matter when you have likeable characters? The visual effects are excellent, bar one scene right near the end where the Dan Forrester character suddenly seems too big in comparison to the alien, but other than that everything looks really good. There is some stand out action scenes, lots of guns, fighting aliens, and even some nice character interaction with the odd one liner thrown in for good measure.
The Bad
J.K. Simmons is so underused in this film, the scenes he is in really stand out, and although he gets some great lines, I do think they should have shot more scenes with him in. That really is my only complaint about the film.
Overall
At 2 hours and 9 minutes, the film seems a bit long, and in some ways the final "act" almost feels like it could have been a sequel. There was a lot more they could have done when they return to present time, and the final battle seems a bit rushed.
With all that said, I really enjoyed the film, and when my complaints boil down to wanting more J.K. Simmons and the final act that could have been a sequel, then you know you have a good film
I score The Tomorrow War a very strong 8/10
I thoroughly enjoyed it.
THE TOMORROW WAR premieres July 2, 2021 globally on Prime Video https://amzn.to/3dpVVl6
