Mad Max Fury Road. They defeat the tyrant, and get the control of the water valves. Then they open the valves and seemingly keep them open. One problem, how long is the water reservoir gonna last now?
Logan’s Run. The city dwellers are freed from the computer’s iron-fisted rule, and Carrousel. But their city is in ruins, and thinks to the computer providing everything. They don’t know how to live without it. The city dwellers are going to start dying off real fast.
Japan has a word which I forget, but it means “Furry Bad End”, which refers to any “Happy” ending where a cool animal character turns back into a boring human; e.g. Beauty and the Beast.
Starship Troopers. The bugs weren’t actually aggressors, and the big one they caught at the end was just scared and sort of cute.
The main character started as a neutral, somewhat open minded guy and ended up a heartless war machine who drank the fascist kool aid and helped recruit new soldiers for their unjust causes.
Samurai Commando Mission 1549 (spoilers for an obscure movie follow)
The Japanese self defence force gets sent back in time to defend the future from the japanese self-defense force sent earlier back in time who is trying to derail history for… no reason really. This is apparently destroying time itself by altering history!
They stop them by blowing up a bunch of stuff and leaving tons of modern tech (including a nuclear weapon, helicopters, tanks, tons of automatic weapons, and an entire oil refinery) in feudal Japan. The movie suddenly ends on a freeze-frame with characters smiling, but none of these issues addressed, which I always understood to mean that they failed and time was destroyed, leaving them forever frozen in that moment.
The movie was unexpectedly hilarious overall. The guy that hosts Iron Chef is in that movie, and is the best character.
In Small Soldiers, the whole problem starts when a corporation being lazy and and lacking any regulation puts military grade AI chips in a bunch of children’s toys. In the end, the CEO flies in on a helicopter, writes everyone a check for their silence, and fucks off scot-free.
The Good Place is one of the best shows ever but in the end they basically just re-invent mortality. In the real world you die and we don’t know what happens, in the fiction at the end of the show you die and then spend some time aligning yourself to the standard the main characters set, and when you eventually align with their morals for long enough you either stick around and atrophy until you’re a forgetful idiot or you…die, and we don’t know what happens.
The viewers of the show see bits of Eleanor falling to Earth and inspiring people but the characters do not know what happens.
If you want to get deeper, Michael the demon is granted mortality which means it can be done, it is shown as a special exception but over the course of infinite time either all demons will earn special exceptions and humans will eventually die and be unable to progress through the afterlife because there are no demons left to guide them through, or that doesn’t happen in which case humanity will die out first and the demons will be left with nothing to do for eternity because all humans will eventually work through the system and disappear.