Namco Bandai have announced that an upcoming free patch for http://www.trueachievements.com/game.aspx?gameid=2119
will add online co-op to its Scenario Campaign, as well as a new co-op leaderboard.
Players can expect to download the free TEKKEN® 6 online co-op update on January 18 for the Xbox 360. Now for the first time in the TEKKEN series, players can join a friend online and fight side-by-side for some serious iron fist brawling.
Previously playable only as an offline single player mode with an AI companion, TEKKEN 6’s Scenario Campaign mode now let’s two players come together online and power their way through numerous stages. Use voice chat to work together strategically and beat down vicious opponents and their legions of minions. To keep the fires of competition in the forefront, a co-op leaderboard will be implemented so players can size up their skills against the best in the world.
This update will also include the following refinement:
· Improved Mokujin AI – In online versus mode, Mokujin’s fighting style changes with every round
The patch will just be a free title update, downloadable from Monday 18th January onwards, whenever you start up the game.
It's probable that time constraints prevented the game from shipping with the functionality, but it's better late than never I suppose. Will definitely make all of those Scenario Campaign achievements a lot easier.