I have a complaint. you know the button beside the name of your level? the one where it looks like it means take a page down? to the left? Well I HATE that button SO badly!!! I was just messing around with my city and accedently pressed it when it was all on fire! The two things that might help is if it will give you a warning OR if you got rid of it.
i agree with a confirmation when clicking it. if you saved it messed up, you can go into the save history and load an old version and save again. its the '7' looking button at the bottom left in the browser. EDIT: the icons of them aren't always right, but just click on them to see
well you can fix it press the seven at the bottom left of your save while browseing then it will show you lots of pictures of your destroyed city ect. confusing click on one of them asnd it will show you previous saves
I don't even know what the button does (or do I). Is that the heat transferral one? Some saves heavily depend upon that and so it would not be a good idea.
... no, its the "save under current name" button it immediately saves, even if you didn't mean to. but as i said, the history function can revert your save back. THE THUMBNAILS ARE WRONG, they all look the same, ignore that part, just open the most recent (top left) for the previous version which should not be messed up.