.smc rom are needed in order to play.
Keys are mapped as followings, you may need to click on the canvas or click the full screen button to let the canvas get the focus.
S9xMapButton(SDLK_RIGHT, S9xGetCommandT("Joypad1 Right"), false);
S9xMapButton(SDLK_LEFT, S9xGetCommandT("Joypad1 Left"), false);
S9xMapButton(SDLK_DOWN, S9xGetCommandT("Joypad1 Down"), false);
S9xMapButton(SDLK_UP, S9xGetCommandT("Joypad1 Up"), false);
S9xMapButton(SDLK_RETURN, S9xGetCommandT("Joypad1 Start"), false);
S9xMapButton(SDLK_SPACE, S9xGetCommandT("Joypad1 Select"), false);
S9xMapButton(SDLK_d, S9xGetCommandT("Joypad1 A"), false);
S9xMapButton(SDLK_c, S9xGetCommandT("Joypad1 B"), false);
S9xMapButton(SDLK_s, S9xGetCommandT("Joypad1 X"), false);
S9xMapButton(SDLK_x, S9xGetCommandT("Joypad1 Y"), false);
S9xMapButton(SDLK_a, S9xGetCommandT("Joypad1 L"), false);
S9xMapButton(SDLK_z, S9xGetCommandT("Joypad1 R"), false);