Masahiro Sakurai often emphasizes the underlying complexity of Super Smash Bros.; with good cause. His team is no doubt furiously finishing off the Nintendo 3DS version at present, before attention will shift to the Wii U iteration that's due in the Holiday season.
In his latest Famitsu column — translated by Kotaku — Sakurai-san goes into a little more detail on the challenges that face the debugging team, as they painstakingly look for bugs and errors that can then be fixed prior to release. In fact, it's this process that's highlighted as a reason for the 3DS and Wii U releases being separated.
Checking is done both domestically and overseas, so for a game like Smash Bros., several hundred people are employed. So, debugging alone becomes a huge project. So much so that one of the biggest reasons for the separate release dates for the 3DS and Wii U versions was so that we could shift the debugging periods.
Some of the problems found can be surprising, and the rare nature of some errors perhaps explains why a number of games ship with bugs that are then fixed in post-launch patches. Nintendo, for its part, still aims to finalise the product as much as possible before launch, even if it's now also more active in issuing software updates.
In a previous Smash Bros., we found a bug during the debugging process where if fighter A hits item B and fighters C and D are simultaneously affected, the game would freeze. Considering not only the different fighters, but items, stages, color settings, play rules, and game modes, the number of varying combinations are astronomical. In order to properly debug, every pattern must be tried, but such a task would be impossible no matter how many decades or centuries you take.
There are many reasons why a game's release date will be delayed, but eight or nine times out of ten, it's usually because a bug couldn't be fixed in time. But it's better than releasing a product like that.
We're certainly hoping that no late bugs delay the Wii U version, in particular, which is yet to be given a firm release date. That said, Sakurai-san's devotion to detail bodes well for the final games living up to expectations.