I wish there was a backwards compatibility option to give applications a “virtual display” which runs in a window, for old programs which only know how to run fullscreen at 1024x768.
I was playing an old MMORPG called The Realm. It's been live since 1995 and ran until just a couple months ago. It only knew how to run in 640x480.
I tried to write a program that would create a scaled up version, but it didn't work well, especially since the game would create child windows for certain UI elements. I was writing it in C, which isn't my strongest language, simply so I could call Win32 APIs more easily.