Kojima has managed to gamify the ack of walking in a game. I, and I'm sure most of us here are used to just pushing the joystick forward and having your character automatically move in that direction. Here you have to pay close attention to your balance and where you're walking. After a while you stop paying attention to the "press L2 or R2" button prompts to balance the character and just start looking at the animation and react to that.
You can definitely see how this game is not for everyone. If you are looking for constant explosive stimulus or big action scenes, you won't find them here. What you will find here is almost an introspective experience. You walk through the landscape and you actually have time to think about anything, it might be about the game, it might even be about your own life. You get into this flow while walking and you really get very focused on your movement and how to get where you need to go.
The game can be very frustrating when you don't calculate your route. Today I took a wrong turn and got to a place I was not supposed to be yet and I had to go all the way back to where I was. Since I wanted to arrive to the right place fast, I made a lot of mistakes and got caught 4 or 5 times by the BTs. By the time I arrived to the correct destination, all of the packages were damaged due to the time fall, my stamina was at zero and Sam couldn't stay upright for long. I sat at the terminal floor and started rubbing my shoulders and feet (something you can do on the game), while being completely covered in the black goo BT's leave on you. I laughed because it honestly felt like having a terrible day at work. I have never felt that way before in a game and after 7 hours I'm looking forward to see what other places I will get to explore.