Good morning "shep"
In Windows 11, the Magnifier tool no longer allows you to reduce the display below 100%. It only serves to enlarge the image. To achieve an effect similar to the 75% reduction available in Windows 10, you must use the scaling and resolution settings in Windows 11.
" Helpful tip"
If your only goal is to play Flyordie on a smaller screen, the simplest solution is probably to use your browser's zoom feature. This replicates the exact same effect you had with the Magnifier in Windows 10, without changing any of Windows' global settings.
Browser Zoom (if you're playing via browser)
Open Flyordie (snooker).
Press Ctrl + - to zoom out.
You can zoom down to 75% or even less.
To return to normal: Press Ctrl + 0.
This is the simplest solution if the problem only affects this game.