“Assassin’s Creed Unity” won’t launch until Nov. 11 in North America and in Europe on Nov. 13, two weeks after the original launch date of Oct. 28.

“It’s the little things. A tiny gesture that Arno makes as he’s racing across the Parisian rooftops. A barely noticeable reaction from a solitary NPC in a crowd 3,000 deep. … It’s these little things, multiplied by the thousands, that a development team focuses on during the final push to ship a game,” French developer Ubisoft explained in a recent blog post. “And with a massive open-world title like ‘Assassin’s Creed Unity,’ all those little things add up fast. Toss in the fact that ‘Unity’ has been built from the ground up as a new-gen Assassin’s Creed – and that final straight-line sprint to the finish suddenly feels like an obstacle course laden with curves, hurdles and pitfalls.”

The historical action game will only be available for the Xbox One, PC and PlayStation 4.

“This being a fully next-gen game, it requires a lot of work, a lot of production and a lot of learning,” said senior producer Vincent Pontbriand. “It’s always hard to be precise and to quantify exactly how much work is involved. So as we get close to the finish, we often realize we’re near the target but we’re not quite there yet.”

“We rebuilt most of the systems,” Pontbriand added. “Sometimes to improve the experience. Sometimes to improve the gameplay itself. Sometimes to reskin it, to make it look fresh all over again. Or sometimes because we had to make everything online-compatible.”

Ubisoft told fans that one of the reasons for the delay is the sheer size of the game, which is significantly larger than previous titles. The in-game city of Paris is larger than the entire setting of “Black Flag.”

“Making games is not a precise science. It’s a leap of faith. There’s a good level of subjectivity and creativity,” Pontbriand explained. “We have a bunch of us who have spent two, three years or more on this project. It’s a huge personal investment. People have been truly dedicated to this game. For them it’s also important to make a game that they can be proud of.”