For sudoku, it worked out that the balance was awful. I imagine if I put in the absolute minimal clues for 3d sudoku it would be challenging and have some more advanced techniques. It just wasn't a good game.

Don't get me wrong, there is probably some niche of players who would like that, but I wasn't going to do the last 90% of polishing a game, writing a solution evaluator, and probably having to play it a ton just to finish it off.

I did end up getting some interviews based on the game. It's amazing how well it worked for the games industry where they have well over 90% of people applying with nothing tangible to show on their resume or portfolio.