Metal Gear Solid 5: Ground Zeroes, the prologue to The Phantom Pain, was almost released right after Peace Walker and according to Hideo Kojima, it could have been either PSP or PS3 title.
Speaking in an interview with Kotaku, Kojima said Ground Zeroes didn't release as planned due to "development issues."
"Honestly, I really wanted to release Ground Zeroes right after Peace Walker," he said. "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 being the way it is now."
Kojima said he decided to release each game independent of each another specifically for the fans.
"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: Ground Zeroes is coming to PS3, PS4, Xbox 360 and Xbox One in northern spring 2014. It is a prequel to Metal Gear Solid 5: The Phantom Pain.
It was revealed last night during Spike’s All Access PS4 launch event that Metal Gear Solid: Ground Zeroes will contain PlayStation 4 exclusive content containing a mission in which you play as Solid Snake, from MGS, MGS 2 and MGS 4, as opposed to Big Boss, the Snake seen in Ground Zeroes and The Phantom Pain.