Sekiro will have a day/night cycle, with tougher enemies appearing at night.

It’s an open world with dynamic weather and a day/night cycle. At night, stronger enemies will appear more often.

Miyazaki says Sekiro will be like Dark Souls 1 in the way that it interconnects, with multiple paths between each area - "with some exceptions." Players will also have choice in the order they complete the game in, From confirmed.

*The video began with Sekiro standing on tree branch then he jumps and uses the grappling hook to reach the rooftop from afar.
 
*He spots the enemy on the ground and uses a special attack to assassinate it. (same attack from twitter 5 secs preview)
 
*When he's in the small building, there's old creepy woman walk slowly toward him, he hides near the door then uses assassination move, She’s dead in one-shot.
 
*Then we saw he switches between his trick arms, seem like you can equip more than 2 at once.
 
*He uses the ax to break enemy with a wooden shield, it’s the heavy vertical chop (same attack from E3 trailer) but then we saw he swings the ax horizontally 3 times before chop. So trick arms aren’t just one special attack, they have their own movesets.
 
*At the courtyard, there are plenty of enemies. Among them is one giant, who seem to be captured? (his head and hands are locked in wooden pillory) Suddenly, one small enemy on the wall spots Sekiro and rings the bell to warns others. Sekiro kills it off by throwing shuriken (or kunai, I'm not sure), but it's too late, other enemies rush at him.
 
*The clashing sword is really the main theme here, You has to parry opponents attacks back to back. The flow is much faster than Souls.
 
*Player struggles to keep Sekiro alive then the giant breaks free and join the fight. It hits hard, only two heavy attacks and Sekiro is dead. Big red kanji appears on the screen.
 
*Enemies are walking away, the player uses resurrection and sneaks behind enemies
 
*Sekiro stabs foot soldiers in the neck, they die instantly but the giant endures the attack. Sekiro uses something that emits red/purple cloud, the giant can’t see for the moment. Sekiro attacks again and the giant’s on fire, same as Sekiro’s sword. He finishes the fight with brutal execution kill.
 
*There's a lot of blood during the fight but it’s brighter than Bloodborne’s blood effect.
 
*He can parry mid-air.
 
*I assume small orange kanji when the enemy uses special attack means that attack can’t be parry by the sword, he can use the trick arm to counter it though. (The animation is pretty cool, locking enemy weapon with the arm then counter it.)
 
*In the next area, a big wooden bridge is broken so he jumps to a faraway tree branch and drops to the lower floor.
 
*It’s a big leap which would hurt you badly in previous souls games, but seem like Sekiro take no damage at all.
 
*In the snowy valley, the enormous albino snake appears. We saw only the head but we can tell it’s so huge. Sekiro hides in the bush, waiting for it to turns away.
 
*There’s red aura around the screen when the snake is suspicious.
 
*When the snake looks somewhere else...Sekiro rushes to the cave nearby, but It notices. It hisses and attacks immediately (this is quite a jump scare, a lady near me jumped so hard), but the cave is too small, the snake can’t get in so it retreats.
 
*There’s a secret door on the cave wall. It has a white human sign on it (looks like it was written with chalk), he pushes it then it leads him to the new route.
 
*Sekiro walks toward to red bridge then Corrupted monk jumps down and boss fight begins.
 
*The scenery is beautiful with maple trees, those leaves on the floor float and move along your movement.
 
*There’s a fog door at the entrance when the boss appears.
 
*After relentless parrying, the boss kneels and Sekiro executes riposte. The music changes when the boss begins phase 2, the surrounding is getting blurry, all color disappears you can see only in black and white. The monk warp here and there, strikes Sekiro from the blurry cloud, then he dies and the demo ends.
 
*Small tidbits
 
*You restore health by drinking from a calabash, a green kanji appears when you drink.
 
*I can see why they don’t release this footage for the public. There are screen tearing and frame rate dipping all over the place. It doesn’t look polished at all. I’m quite certain that this is an old E3 build.
 
*I recorded the audio, but the quality is REALLY bad (lol I'm sorry I tried). If you interested, you can download it here.r/https://drive.google.com/file/d/1lPQGCqs_yiF49ktaFMgomIEtxkRYcdPs/view?usp=sharing
 
Some explanations~
 
0:00-1:00 - He jumps around those trees and rooftop.
 
1:00-1:15 - Encounter enemy, parry&riposte
 
2:00 onwards - more enemies
 
3:08 - Trick arms swapping
 
4:27 - An enemy alerts the other
 
4:44 - Giant fight
 
5:25 - Dead and resurrection
 
7:40 - Giant snake
 
9:03 - Boss fight
 
11:00 onwards - Phase 2
 
That's it! I hope this info is helpful for some of you guys until they release direct footage at Gamescom.
 
p.s. They let us have this nice collectible card after watching the footage. If you go there don't forget to ask for it.