Main game
3.55 average rating based on 11 ratings
I did it! One hundred percent, baby!
Once you beat the last puzzle, you unlock "Expert Mode". It's the same as Normal Mode, but you can't mark squares with an "X" anymore (though if you complete an entire row/column, it still automatically fills in the Xs). You basically restart with the easy puzzles again, and there are a couple dozen additional puzzles added (and some new music is unlocked). You can't choose which puzzle you do. The game randomly picks one like it did on the first playthrough.
After trying a 15x15 Boss Puzzle in Expert Mode.... I think I'm good. I don't hate myself enough to try to beating Expert Mode. :D
This has been a fun pasttime for several months. Unfortunately, tonight I just hit a wall where the only unsolved puzzles left are time-gated Boss Puzzles --- about 75 of them. I'm not entirely sure why they're even time-gated, since you can't pay to unlock them or anything.