You have to use the second controller........hhmmm....... :blink:
Unless someone writes it into the emu to use the breakout box to hook up an extra controller, you'll have to be content with one player.
Well, you can't, unless you somehow change the key mappings, though I'm not sure if it's possible to do this simply by changing the config files. On another note, would it be terribly offending if I asked you to reduce the size of your signature? It's too big and distracting, and has too many images on it...
Before I went somewhere, there was a post here that said a second player appeared while they were playing metal slug. under the post, there was a explanation on how to press start as second player. It was something with the stick and another button. I have forgotten. Can find how to press the start in second player?