- Two modes. a) Collab, b) Compete.
- Collab
- Multiple players play on the same sudoku board.
- Google docs-style cursors to show the boxes a user is looking at.
- End of game, show stats on number of boxes filled by users. User with more boxes filled wins.
- Teams can compete.
- Compete
- Same puzzle, different boards for each player.
- Shortest time - wins.
- Can be played async, I play today and same puzzle gets sent to my friends tomorrow.