First, install the game (you need a virtual machine), then go to c:/space/ and make a copy ENG_LANG.DLL named _LANG.DLL. Run INSPAXE.EXE and play!
Three add-ons were released; a Ship Builder's Kit and two add-ons: the Military and Nations of The World ship sets, which add military ships such as tanks and World War I and World War II planes. These add-ons were combined and released as "The Works!", which includes sound and voice packages that are available separately.