It depends what emulator you are using. However most have an option to take a snapshot (from top menu) which is an image of the game at that time. This is basically a save game, and to run it just select load snapshot instead of loading up game. Hope this helps as the game would be impossible without a save function.
Lee
Ps Has anyone managed to compltete the double? I managed it a couple of months ago for the first time but as this was on emulator i feel like a cheat as a seaon only takes a couple of hours. Anyone managed it on C64?