what's the difference between deterministic patch and regular version of red ball 1?

and also what is IGT edition?

Deterministic patch: Screen-scrolling tweener is bound to 31fps frame timing instead of inconsistent system timing, so spike glitch is consistent and the camera isn't jerky. You can read more about it at https://www.speedrun.com/redball1/news/k06v756m IGT edition adds a timer to the screen. If it's green you started moving on the first frame.