I tried ’88Games and I my coin (Select) button did not work like yours (this game works fine in FBA?).
I tried other few games and they were ok (Mortal Kombat, Snow Brothers, Samurai and NBA Jam).
I tried Moon Walker and it failed so I guess I will try it in FBA later.
I tried Run N Gun as well but it said the game is not supported (my rom set did not have this game included but I really would like to be surprised… hehehe).