- On a scale of 1-10, 1 being you could do it with your eyes closed, 10 being you thought it was nearly impossible, how difficult was this puzzle for you?
- Did you learn something new because of this puzzle? Could be something about your language or a library or a new algorithm that helped you solve it.
- What language(s) did you use to solve this puzzle?
It could let you compare yourself with other developers - if you thought it was hard and most others didn't then you would know you might need to practice something more. It might be something that would best be combined with some profile level questions - like their experience level and primary languages that they use day to day.
It could tell us that people who used python found this particular puzzle easy (maybe because of some built in function in the stdlib) but people using some other language didn't.
Year over year it would be awesome to compare the languages that people use. Nobody is doing this for their job supposedly so these are either languages that people enjoy or find practical. I bet you'd find some correlations though too between language and how many puzzles they complete in a year - ie people using language x tend to finish the whole year but language y tend to drop off after day 10.