There used to be a mode or map on LAN play that was called "Red Storm". It was a series of 4 or 5 maps where you played non-korean Allies vs soviet AI , 2v2, difficulty "Brutal". There was actually more than 2 series but Red storm was the funnest.
It doesn't look like these maps/series are available in CnCnet. Someone else pointed this out a while back
https://forums.cncnet.org/topic/6190-red-alert-2-original-coop-missions/
I guess the issue is that the YR co-op maps are there but not the RA2 ones
Thanks
