A very minor update to say that I've enabled Steam Cloud for the game.
This means that when you exit the game, saved games will be uploaded to Steam. If you play on another computer, you still have access to your saves.
If the upload causes a problem for anyone - the files are up to about a megabyte each - then this can be switched off in the settings on the Steam Library page for the game.
One other thing: I'm currently testing Steam Achievements. These will be made available in the next update.