7 reasons this movie was written by a drunken brain damaged 6 year old.
1. Only people who are not born yet are allowed to travel to the past to avoid paradoxes. After the bridge to the future is destroyed, they remain in the past, which means they will still be around when they are born.
2. Why even bother trying to explain why they can only build just one portal to the past. "we didn't have time". or something. Riiiiiight.
3. So you can travel to the past, and your idea is to collect people from the past to bring them to the future to fight an unwinnable war. Not to send people from the future to the past to defeat the aliens before they bred and took over the entire planet? Riiiiiiiiiiiiiiiiiiiiiiiiiight.
4. How does time travel work anyway? If Chris Pratt travells to the future 7 years before he died, shouldn't his daughters memories of what happened to him change? None of this makes any sense. Parrellel timelines? But then why do paradoxes matter? I guess if you don't even bother trying to explain anything and make sense, then it doesn't matter right? OK.
5. Which part of the plan required his daughter sending him to the future again? She said that there was a reason she sent him to the future. But anyone else caught have brought the toxin to the past. Makes no sense. But what does in this movie?
6. They decide to take on the aliens with a small group of sodliers, because goverments or something. OK. I guess I will just accept this ridiculous childllike writing and try to enjoy the film OK? nope.
7. The whole plot was built around the toxin, which didn't actually play any role in them defeating the aliens in the final act. In fact, if they had just blown up the ship instead of injected half a dozen aliens with toxin and waking up all of the others, everything would have been done and dusted. Instead, they wake them up, let one escape, blow up the ship, then have a silly fight with the one that escaped. Every other stupid plot-hole into the movie I can kind of understand people who are not very smart accepting, because time travel is confusing and all that. But this was just duummmmmmb. Someone got paid a lot of money to write this script. And this is what they came up with? Utterly ridiculous.