I appreciate the alternative, but creating a button did not work for me either (although I agree that it should have).
Something happened to a sprite text on one of my saves so the list only shows "Lv1-0" instead of "Lv1-01". I have since fixed that and when I export the game to my phone this change shows. It shows in C3 itself, but when I do the preview layout or project, it still shows the old incorrect sprite font and doesn't reset the game proper.
The way I fixed it was to disable my load button and have it reset the defaults for when the load fails (when there is no save data).
All this to say... this process should be easier. While convoluted, I feel C2's "just delete the files on your computer" method was easier and quicker (once I found out about that answer that is).