It uses DOSBox. I have included a utility to make it easy to change some of the settings from default, but otherwise the game seems like a native Windows app that starts from a shortcut or from "Gold Rush!.exe". The sound is set to use Tandy sound, so instead of PC speaker, it has the PCjr/Tandy three voice music plus noise channel for sound effects. Also worth noting, this is version 3, which has no annoying manual check copy protection. There are illegal "abandonware" copies floating around on the net that have been crack in a way that makes it impossible to progress much beyond the very beginning. For this version, the MacNeill brothers removed the copy protection all together.