Other versions of Ground Zeroes remain at the same price; you can check out the game's still highly-convoluted pricing structure here. Incidentally, the price cut is matched in the UK, where PS4 and Xbox One retail versions will set Brits back £30.
In addition, Konami confirmed the previously speculated inclusion of Phantom Pain DLC with early purchases of Ground Zeroes. The codes, which include additional staff to utilize in Big Boss' Mother Base headquarters, which apparently plays a "central role" in The Phantom Pain, are available in the first batch of retail copies and for an undisclosed "limited" amount of time with download versions. In case you've been living under a rock or with bandages wrapped around your ears, MGS5: Ground Zeroes is being billed as the prologue chapter to MGS5: The Phantom Pain.
If you'd rather wait before you Snake, the good news is all copies of Ground Zeroes have some integration with the Mother Base in The Phantom Pain. The POWs and VIPs you rescue in the prologue will carry over to the follow-up, as will character skins you unlock.
Finally, it wouldn't be Metal Gear without some peripheral capers, and if you so choose you can download a free second-screen "iDroid" app on iOS and Android to use with the game. The app, which is integrated into SmartGlass for Xbox, lets you view maps, play cassettes you discover, and summon air support in the game ... Oh, the game! Yes, the small matter of Ground Zeroes itself arrives on March 18 for PS4, Xbox One, Xbox 360, and PS3.