Bug-testing is a critical part of game development, and for Super Smash Bros. for 3DS and Wii U, it sounds like an incredibly complicated and challenging endeavor. Game director Masahiro Sakurai writes in his latest Famitsu column (translated by Kotaku) that there are an “astronomical” number of sequences that Nintendo must test for bugs, which makes sense when you consider all the fighters, items, rules, modes, and more that are featured in a game like Super Smash Bros.

Sakurai says “hundreds” of people are currently debugging the 3DS version of Super Smash Bros., which is set to launch on October 3. The involved nature of bug-testing a game like Super Smash Bros. is one of the reasons why the 3DS and Wii U versions are not going to be released at the same time–the Wii U version is coming sometime this holiday.

“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” — Masahiro Sakurai

“Checking is done both domestically and overseas, so for a game like Smash Bros., several hundred people are employed,” Sakurai said. “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.”

“Considering not only the different fighters, but items, stages, color settings, play rules, and game modes, the number of varying combinations are astronomical,” he added. “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.”

The bug-testing process is so critical, Sakurai says, because it would be very problematic to ship a title that had a game-breaking bug. He revealed that for a past Smash Bros. game (he didn’t say which one), developers found a bug that froze the entire game. In this instance, when fighter A hit item B, fighters C and D were also simultaneously affected, resulting in the bug, which was later fixed.

Finally, Sakurai said most of time a game is delayed, it’s because of bugs. But even though fans–and sometimes investors–might be dismayed at the idea of a delay, pushing a game out further is better than shipping a busted game, he said.

“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,” Sakurai said. “But it’s better than releasing a product like that.”

Earlier this week, Sakurai released images of a new costume set for Zero Suit Samus.