Well...it's not really a game, just a short 'renpy comic' that Stoper did as a quick side-thing for his patrons.
And it's two old men plus her husband. Can you really classify that as a gangbang?
Isn't it a foursome?
Is three men a gang?
If it is, I'd say that's a pretty-small gang. More like a trio.
I've just googled it and according to the rules of the International Gangbang Federation (IGF), you need at least 5 men for it to be classed as a proper, bona-fide, genuine gangbang.
Just saying.
The other sentiments I totally agree with, for what it's worth.