A variable also tracks the states of major game keys, i.e. the cursor keys, control, and alternate. Scanning the keyboard for game purposes becomes are real chore, but checking variables is a lot easier. I believe a new keyboard interrupt is a must for game programmers, just remember to turn in on and off or you'll lock up the system. This makes it possible to do timing calculations in games and things. My best use for it is to act as a synchronization tool.
Games require different framerates on different computers because of a computers limitations.
I use this to allow things to run at the same actual speed on different machines but still allow for smoother gameplay on faster computers. It allows 3D wire-frame graphics to be created without much trouble at all. In the future I hope to enhance this to be really cool, but that all depends on how much time I have. My ultimate dream is to create 3D outdoor worlds with Quake quality graphics and speed, but I have nowhere near the expertise required to do that at this point. Actually, it works well enough just scrolling, I never actually did anything interactive with it.