Thanks Gramphos, I may well take you up on that offer (again)! Both your online docs on Apolyton and your PM responses have been a great help to me in getting this far . What I was really hoping is to avoid people suggesting features based on information that can't be extracted from the .SAV because it's not there. Most of the .SAV is a snapshot of the game state at the point the .SAV was saved. There isn't all that much that can be replayed over time. I.e. can't replay all unit movements because we only know the unit's current position, not all of their previous positions.