Minor complaint.
Watching it the second time, I wished the snap would have shown more populations vanishing across the universe. They have introduced so many worlds across the MCU, with the Guardians and Thor movies.
To really hammer home that this is a universal extermination, it would have been a nice and poignant callback to show all of these races being wiped out in a montage. And it would have felt like even more of a culmination of these 18 stories, watching "evil" and "good" races suffering the same fate. Instead, as it stands, it felt a little too earth-centric.
I feel like I know why they didn't do that. They wanted all of the focus to be on the heroes dying. That is who the audience cares about. And cutting away to characters we don't know or have a personal connection to would have undercut the emotional shock of seeing people like Peter and T'Challa go.
I get it. Don't spread the emotion too thin or share the moment with anything else.
But I still think they could have worked it in there, perhaps after Dr. Strange and Peter die on Titan. Maybe they could have cut to the wider universe and then fade back in to Thanos on the farm, coming to terms with fulfilling his mission.