How about exporting a Tab Delimited Log? Perhaps the Submit answer command has a Log option pop up, or perhaps there's a Submit w/Log command/option. The data would include just about "everything", but most importantly the User, Date, Time of Day, Level, Time to Solve, Success??, # Retries, Hint status & number of hints -- etc.
Basically, this allows one to generate useful spreadsheets to track performance. There are many articles on using Sudoku to treat/ward-off Alzheimers, etc. (Personally I'm using it along with Chess to track recovery from an illness). The inherent facility of a Spreadsheet handles all sorts of history desires. Useful Spreadsheets could be shared here in the user community.
It's sort of embarassing posting a wish against such a really well thought out and cleanly implemented program - I do so with great humility.