I didn't know the sole purpose of Metro was a game for people to find bugs in.......I actually thought it was an app for audio and midi.
I do report what I see when I come across something odd (still waiting for VU's that go across the screen) but still hope Jerm has hair at the end of it all.
I should point you to
www.fools-errand.com/ which currently has 3 old puzzle games on it from the 80's and 90's which are much harder to complete than looking for every minor bug in metro.
If you stay round long enough on halloween the author is releasing a sequel to his original 16 year old program. Better late the ever!
I am not plugging the guy's product just remember enjoying playing them in the past and they're free to download.
Somewhere in the games I am sure there is a solution to your audio setup problems so your time won't be wasted.