It therefore requires a system environment either a Mac OS prior to OS X, or at least one OS X - version which still supports the "Classic environment". While this contributed probably the first OS X versions yet, but the newer of the last few years just no longer (Sorry, I do not know from which version of OS X Classic environment is no longer supported).
Hence my recommendation: Check out before 'nem purchase first, what OS version your Mac has and if there because' ne OS X version ner whether that still supports the Classic environment, so you can install the game at all.