That was made by Jeroen Tel, one of the wizards of the C64 music scene. See this...

		selcuka 45 days ago \| parent \| context \| favorite \| on: Monkey Island for Commodore 64 Ground Up That was made by Jeroen Tel, one of the wizards of the C64 music scene. See this for another example of a technical feat with the SID chip: https://www.youtube.com/watch?v=qYnwR16NbPE