What computer auto-shutdown timers can you recommend (to control the time spent on the computer)?

Question

Google

I am using Windows.
You want the timer to warn the user that the computer is shutting down for a certain period before the shutdown (need to be configurable), but the user is NOT allowed to cancel the shutdown.
Let's say he plays a game, and 5 minutes before shutting down, a window pops up on top of the game and warns him about the imminent shutdown so that he can save the game and exit it.
I just looked on the net, but there are all the timers with the ability to cancel the shutdown. This doesn't suit me.

Answer 1

shutdown -s -t 30
Issues a warning and cuts down the car after half a minute. Irrevocable.
Can be put in Scheduled Tasks.