Sudoku has been an underrated game. They think it's just a simple fill in the blank with numbers and just solve it. But this game used that idea and turned everyone's thinking upside down. It's a really neat and cool game. The graphics are cute and the music is great. The speed and the leaderboard system feels like the game is very polished. I'm impressed that you can make it in under a week.
No matter how good the game is, there's always something wrong with it. There are slight bug issues where the player can't modify their equipment after beating the boss, and that caused the equipment to disappear from the inventory. Also, I feel like the sudoku could be improved as I saw one empty cell in a column where I know it should be 8 in there, but there's already an 8 in that row. I'm not sure if that's me or the game, but you could improve it if you can.
Overall, I think this is a well polished and great game. I'm hoping you would improve your game and turn it into a real indie game. I'm looking forward to it. Also, if you have the time, please play my submission as well.