I've always liked to play sudoku. Some time back I was playing quite frequently in the web site sudokucombat.com. It enable you to play the same puzzle with another person at the same time. The 1 that finishes 1st wins.

Unfortunately, it was bought over by another company. This company decides to revamp sudoku combat into something not fun. Thus, there's no more good multiplayer combat sudoku.

Recently, i received an email about Subdoku Shootout The game play is similar to sudoku combat. Now I hope the user base goes back as well.