I already tried a proof of concept by exporting my Analytics page data as csv and then filtering the ones where I missed but my opponent got it. To find rounds that were gettable but I just missed something. Then I made them into a map to practice those specific rounds. I think that would be a nice feature to have, to filter out "difficult" locations or locations that were missed and put them in a map. Even better if after getting the location correct, the location will be deleted from the map. This way you get a direct practice and feedback system like learning cards.