A beta of Red Alert 1 v0.09c Siberian GRemlin found has popped up and is now released. It has cool unused cut scenes, sound files from the thief and allied quotes of "It is done.", a internal scenario editor and all kinds of differences. It's a little tricky to setup but there's instructions and fixes for it.
https://www.reddit.com/r/commandandconquer/comments/dflqti/a_present_to_the_cc_community/