Almost two years ago I found myself frustrated by existing sudoku apps, filled with ads and paywalls. So, I built SudokuSmart iOS for all the frustrated sudoku players like me that wanted a sudoku app actually built for players, not for revenue. This is how I think the app improves on the mainstream:

1. Levels. The app has 756 permanent levels, and new "Daily" and "Weekly" levels - all on average more difficult mainstream apps; for example, the hardest NYT sudokus are rated 5s, but the most difficulty sudokus on SudokuSmart rated 9s (ratings correspond roughly to SE).

2. Hints. The app offers step-by-step hints on any solvable sudoku you input. Many other apps simply show the next number without explanation and call it a hint, especially for difficult grids; SudokuSmart has an intricate and comprehesive solver that actually explains to players how to solve for the next number (including AIC).

3. Differentials. Leaderboards, friends, scanning photos to play custom levels are features which, on their own, might make any sudoku app unique, SudokuSmart has all of these.

On top of this, the app is entirely free (no ads, no premium)