Kojima stated that Volume. 1 (what we just saw) was meant to give us a look at the basic 'gameplay flow' as he described it. We saw Sam tasked with delivering items from Capital Knot City to Port Knot City. On the way, we ran into MULE forces, a Musician prepper and BTs initiating a bossfight. Weapons and tools such as Strand and the Bola Gun were used to deal with conflicts. We got a good look at the Social Strand System with players placing ladders, rest stations and other useful things in the environment as we eventually made our way to Port Knot City and established another strand.
KojiPro will show another 30 minutes of gameplay on Saturday. I think this one will take a look at what happens when you 'die' (note: Death Stranding has no traditional game over system, if you die, you're tasked with getting back to your body which ends up causing a Voidout in the environment). I'd imagine we'll get to see what Kojima means about the first-person perspective being important in this bit.
I think Voidouts and the 'death' aspect of this will be the next gameplay focus. Also, we've gotten a better look at how the Beached Things (BTs) look with the BRIEFING trailer. Is that an umblical cord?