Metal Gear Solid Delta: Snake Eater will feature two different control styles, but players won’t be able to freely switch between them.
That’s because the difficulty of the game will be altered to match the control style.
The game’s producers Noriaki Okamura and Yuji Korekado were interviewed by Famitsu and discussed some of the new additions in this remake of Metal Gear Solid 3: Snake Eater.

METAL GEAR SOLID Δ: SNAKE EATER – Official Trailer #2