Sudoku Free (630 Boards)

I enjoy playing Sudoku, and also like developing games. I have never finished making a game. I decided to make a Sudoku game for myself as a learning project, while having the primary goal as finishing it, no matter how it turned out. I have decided to release it here in case others want to play it. The boards start easy and gradually get harder. However, you can pick any board you want. There are 630 boards in total.