Here is the full list of all 57 Sudoku Zenkai achievements.
Completed 50 games.
Completed a daily challenge with a friend.
Completed a 20 winning streak.
Shared 20 games.
Completed a 10 winning streak.
Shared 15 games.
Completed a Fair Sudoku under 10 minutes.
Completed 20 games.
Completed a Pushover game with a friend.
Completed a 5 winning streak.
Completed a Challenging Sudoku under 15 minutes.
Completed a Challenging game with a friend.
Completed a Challenging Sudoku without any helps!
Completed a Insane Sudoku under 20 minutes.
Completed a Insane game with a friend.
Completed a Insane Sudoku without any helps!
Shared 10 games.
Completed a Zenkai game with a friend.
Completed a Zenkai Sudoku under 30 minutes.
Completed a Zenkai Sudoku without any helps!
Completed a Fair game with a friend.
Shared 5 games.
Completed 10 games.
Completed a 3 winning streak.
Completed a Fair Sudoku without any helps!
Completed a Pushover Sudoku without any helps!
Completed a Trainee Sudoku without any helps!
Shared 1 games.
Completed a Pushover Sudoku under 7 minutes.
Completed a game using Last Valid Board.
Completed a game with another emblem.
Completed 5 games.
Played a game with every theme.
Played a game with every emblem.
Played a game with 2 different themes.
Played 50 games with a friend.
Played 20 games with a friend.
Played 10 games with a friend.
Played 5 games with a friend.
Helped a friend.
Asked a friend for help.
Completed a Trainee Sudoku under 5 minutes.
Completed a Trainee game with a friend.
Played 1 games with a friend.
Played 10 Trainee games.
Played 10 Pushover games.
Played 10 Fair games.
Played 10 Challenging games.
Played 10 Zenkai games.
Played 10 Insane games.
Completed a game using a hint.
Completed a game after 30 minutes!
Completed a game after 60 minutes!
Completed a game after 120 minutes!
Completed a daily challenge.
Completed a game without using annotations.
Completed 1 game.