Hmmm..why not add a timer, and with each procedurally generated level, some leveldata that is attached to the score. That way, players can look up that exact level at a button press and see how well other players did - you could automate leaderboards hosting thousands of levels.
Another option is to ditch the level data and just add a point score for beating a difficulty level the fastest. Then users would want to keep playing, trying to get lucky with a maze they beat quickly
Thank you for your feedback. Making some kind of point score and a leader board is a great idea!
I was also thinking of implementing path tracing and direction hints for players who have difficulties with solving the maze. Of course that would be only an additional option which when used would disable the ability to submit your score to the leader board