Small World was created with Inform and has IFID D07A20DE-FA69-451C-AD24-F32B1D159E05. To play a work like this one, you need an interpreter program: many are available, among them Zoom
for Mac OS X and for Unix; Windows Frotz or Windows Glulxe for Windows.
Or you can play without downloading anything by following the 'Play In-Browser'
on your web browser.