You can indeed turn off improvements in OpenXcom granularly.
There’s bug fixes, there’s UI improvements, and there’s enhancements that improve/change gameplay aspects.
For my money, if you just use bug fixes and UI improvements, you’re basically playing the same game.
I believe many of the fixes have also been introduced to the DOS original by fanmade patches over the years. So you can get a lot of the bugfixes at least, to play in actual DOS environment too! 🙂
