Not sure if its power supply related but I have experienced crash on a number of cores I tested (PS1,GBA,Megadrive) usally after a few minutes or in the case of GBA core (Pacman Collection - Pacmania - screen freeze at title but audio continues at slow rate.
PSU is from a GameStick console 5V @1.5A whilst I note Pi2 PSU is rated 5V @2A.
Also is it possible to configure buttons as I am using microsoft dongle with wireless Tekken 6 arcade stick and set button placement is not ideal in some games.
sidenote I had to set audio to alsa as default alsathread kept dropping out randomly.