Could it be possible to have the total unique words played over all games be included in the stats too? Broken down into the N levels as they are in the current end game summary.
I was thinking under the overall stats below Number of kana words played and Number of kanji words played there would be Number of unique kana played and Number of unique kanji played... Perhaps breaking up into the N levels will make it too messy so that's not needed. Cos after playing enough shiritori games I'm not playing as many new words per game, so I am quite interested in knowing how much total vocab I've actually learned through shiritori. Although sometimes I'm just trying random combinations of syllables for the kana shiritori heh.
Just did one game of kana shiritori to see how it would work... And I think your suggestion works too, so to have an extra row under the current postgame stats where it shows the all time total played for each of the N levels. I love seeing stats heh.
I'll definitely keep it in mind. Right now, I am keeping the changes to renshuu at a minimum as I prepare for my family's end-of-the-year move to Japan. I do have a hefty to-do list, so while I cannot guarantee I'll be able to get to this, I will try and consider it when I have time!