On PS3 gamers can buddy up in a pair and take on another pair online, but it's not supported for Xbox 360. There are always times to "make tough decisions" during development.
This was "one of those times," said Ayano-san. Simply put they ran out of time to include it for Xbox 360 as well as PS3, and as PSN enjoys free multiplayer, why not?
"We've been asked by some players of the Xbox 360 version about the four-player co-op mode and why it doesn't work when two players team up (locally) and attempt to play online," Tomoaki Ayano.
"Unfortunately, due to time and resource issues, we weren't able to get that feature into the Xbox 360 version and we apologise to those players who were looking forward to it. Throughout the development process, there are times when new features are added (and we added a lot of them!) and there are also times where we have to make tough decisions regarding things to cut. This was one of those times."
"This mode is supported in the PlayStation 3 version, however, since we tackled that earlier and found the architecture of their system to be more conducive to implementing it. This is the most content we've ever packed into a Street Fighter game, so we hope that there are plenty of other modes and features to keep everyone busy for a long time."
Street Fighter x Tekken has also been suffering sound issues due to bandwidth of having four players connected for matches. So far there seems to be no solution to the issue. Assistant producer Tomoaki Ayano has promised more updates for the crossover brawler will be forthcoming.