As has been mentioned already, Brolin did a fine acting job through all the prosthetics and CGI. It was also refreshing to see a villain who truly believed that was he was doing was
right -- or at least
necessary -- and that he'd be hailed as a hero in the end.
Of course, he's delusional, given the frickin'
huge flaw in his plan.
So, he plans to save trillions of sentient beings from death by starvation by ... killing them. Okay.
And what, exactly, does he plan to do when, within a generation or two, the survivors have reproduced and brought their numbers right back up to where they had been? Does he think, "Eh, I'll kill half of 'em again, and just keep doing that every few years -- over and over and over again." Maybe, he's hoping, they'll eventually get the message and take steps to ensure that they don't let their populations grow beyond the capacities of their ecosystems to support them. On the other hand, if people were inclined to think like that, overpopulation wouldn't be an issue in the first place.
Even so, if Thanos was
truly interested in eliminating poverty, hunger, etc. -- he
did have all 6 Infinity Stones at his disposal. It's not as if he couldn't have simply wished for all sentient species to now and forever live within the limits of their ecosystems.
***
It was stated that Thanos killed half the surviving Asgardians. So where are they? [Given that the Asgardians had just suffered a
huge population decrease (and didn't seem to be overpopulated in any event) you'd think that he wouldn't have felt the need to eliminate half of them.]
Are they being held captive on Thanos' ship? Maybe so.
Dr. Strange insisted that giving Thanos the Time Stone was necessary in order for the Good Guys to ultimately prevail, so it'll be interesting to see how that works out.
I'm looking forward to Part II, to see how all of this is sorted out. There's no way they're letting Spider-Man and Black Panther stay dead, I'm sure. Vision and Loki will likely stay dead, though, I'm guessing.