Metal Gear Solid V: The Phantom Pain is the final game in the Metal Gear series. It is the sequel to Metal Gear Solid V: Ground Zeroes released the year before and a prequel to the original Metal Gear. The game has a complex story with long cut-scene sequences, but there are fewer and they are shorter compared to earlier Metal Gear Solid titles. Most of the gameplay mechanics introduced in Ground Zeroes are carried over: it is still an action game and stealth oriented but replaces the linear corridor design from most earlier titles with large open world environments that offer the player unrestricted freedom for the approach. The world has now a real-time day and night cycle and various weather effects that influence enemy behaviour, visibility and sound. Sabotaging or destroying certain structures can also influence other parts of the map.
Stuck and need some help? Check out some of the questions the community have asked relating to this game. If none of these answer your problem or you want to get some tips when it comes to a particular level, feel free to submit a question of your own.