I think I've gotten it sussed out for me anyhow. The extra incoming blocking was redundant, I assume that's what was preventing seeing the...
I've been rather back to front. Friend's issue seems resolved, as he actually had a second copy of the game in question running, but not seeing...
I am having a hell of a time trying to figure out what I'm missing, if anyone's willing to help me out: Game firewall rules in place to block UDP...
Separate names with a comma.