Metal Gear Solid 5: Ground Zeroes was originally meant to release shortly after Peace Walker, and is releasing ahead of The Phantom Pain partially because of his own eagerness, creator Hideo Kojima told Kotaku.
According to Kojima, the original plan was to release Ground Zeroes as early as 2010, following the release of PSP’s Metal Gear Solid: Peace Walker.
“Honestly, I really wanted to release Ground Zeroes right after Peace Walker,” Kojima said in an interview with Kotaku. “Whether on PSP or PS3. But then we had development issues, some delays with Metal Gear Rising as well. And then we learned about next generation coming, so it ended up the way it is now.”
So for this reason, and in order to give something to fans while they wait for Phantom Pain, Kojima decided to push Ground Zeroes out sooner.
“Of course it would be ideal to release Ground Zeroes and the main part of the game all together,” Kojima said. “But at the same time given that this week we have the next generation of game consoles coming out, a lot of the fans wanted to play something sooner. And given that the main game is a rather big game and still in development, it will take a little bit more time to get it out. We decided to listen to the fans and put at least the prologue out there so people will get the experience.”
Metal Gear Solid 5: Ground Zeroes is set for a spring 2014 launch on PS4, Xbox One, PS3, and Xbox 360. A release date—or window—has yet to be announced for The Phantom Pain.