You watch this mindlessly, and it is a decent movie with good action & cgi to spend time on. However, if you like to think while watching, then you probably won't like this movie. The story has too much questionable plot loopholes & logic.
<Spoilers ahead>
1. Time travel is possible & humankind had a rough geography of where the alien spread from. Humankind doesn't try to isolate & nip the problem in the beginning. They sent ill-prepared civilians into future to fight the war.
2. I understand the future military doesn't show videos/photos of the aliens to the public is to prevent widespread fear & potential drafting desertion. But for the drafted civilians who are already going into the fight in the next second, they couldn't spare a minute at the very least to say the aliens' weak points are their neck & belly to increase the mission success rate?!
3. The aliens are NOT immune to high-power fire and cold weapons. But of course, the mc has to extract alien mommy essence PERSONALLY to research a venom for killing them.
4. They can send people, weapons & equipments into the past & future. But the important research has to be conducted in a chaotic future environment; they couldn't bring the research back in the past...like are you fr??
5. There are no sensible & clever leaders in the movie. Only the mc & his ragtag team are clever enough to deduce the location of alien nest.
6. The mc & ragtag team went into the nest...and individually HAND-INJECTED each alien with venom. Then the aliens woke & broke out, and someone had to sacrifice with a bomb. Yeah, nobody thought of sealing up the nest & bombing first. Yeah...!
Conclusion, you watch this movie but don't think and you will enjoy yourself :)