fun but very tough! how about sorting all answers by 'unique letter' so that as you go along you get an idea of what to look for? or something like that
Nice, this was 'doable'! Another suggestion in case you want it to be harder: instead of showing the unique letter, have a list of the unique letters on the right, these get ticked as you guess the answers. That way you kind of need to find the first one by yourself (and for example the unique initial letter ones should be easy) but then you get a help. Perhaps it would still be too hard though