During my third degree in computer science, I had to develop a Sudoku PC game with three teammates. I was the team leader. I also participated to the game design and to the programming part.
We tried to create something a bit more ambitious than just a simple grid to solve. We had three different ways of playing. The first is a classic one, with a leader-board and a save system. The second had the player to play against the clock. At first, he has to select a difficulty, on which depends the time he has. If he plays that way, there is no saving. The last is about creation. Players can add their own grid or try to create one. The point was to make the game more social and friendly.
We focused hard on the global graphic design. We wanted to offer to the player a relaxing game to ease his thoughts. The sound design was made in that way. Visually, we worked only with green tints to give a true identity to the game.