None of my children have their own electronics, but rather have to ask for permission to use our electronics. On the rare occasion that we actually let them utilize them, they are told what their time limit is. They also know that once the time is up, that is it. If they are playing a game that requires saving, then it is their responsibility to keep up with the time and to ensure that they have saved before that time is up.
A failure to care about this on their part does not in turn manifest any duty to care on our part when it comes to taking back the electronics. You may try having a sitdown with your kids and explaining that when they are given an hour on the game, that does not mean a solid hour of play time. It is an hour of time with which to select their game, play it, and then if it is important to them, to save it BEFORE the allotted time is up.
Inform them that once their hour is up, you will be walking in and closing whatever game they have open immediately, no questions asked, and then turning it over to their sibling. If they are concerned about saving, then they need to prioritize saving before the timer goes off. If it’s not important enough to them to save, then it shouldn’t be important enough to you.
By doing this, you are putting the ball in their court, and any unsaved games or punishments are purely their own doing.
Also impress upon them that any complaining, fighting, etc… will result in the immediate loss of the privilege of playing the games for x number of days (whatever amount of time you determine is appropriate.) Video games are literally nothing more than a series of electronic signals that come together to produce an image on a screen. It is not real life, but on the flip side, their siblings ARE real life.
A video game will not love you, will not be there for you, and will never offer you anything meaningful. We should never sacrifice harmony in our relationships with a real life person over an uncontrolled desire to press some buttons and watch lights flash on a screen.
We should love people and use things… not the other way around. By loving a video game so much that we are willing to take time away from someone else, or to fight with them over it is an example of us using and manipulating a person to better serve our love for a thing.