There could be a sysrtem. There are two different buttons: Keyboard (A,B,C...Y,Z...1,2...9,0...plus symbols) and player (jump, run, pause etc.). You can detect, if the button is pressed, hold, and released.
You know how that you can change the sfx in the world map editor for Episodes? Well, can there be that same system, but each character produces a different sound? Like, I want Marios Jump SFX, to be different than Luigis Jump SFX. I would prefer if that was an option you can set, and not be by defa...
The links do not have a virus. Deactivate your antivirus temporarily and then exclude the folder where you have your SMBX. Then you can turn your antivirus back on.