So up to a year ago and at various points during that time I would come up with story scenarios for Halo Infinite that might show up at E3. I suppose now is as good a time as any to share what I came up with, what I had envisioned Halo Infinite to be. I’ve come up with alot of other ideas and scenarios which include the crew of the Spirit of Fire and even possible interactions with Mendicant Bias, and the revealing of how he brought the Spirit of Fire to the Ark etc etc. But for now I’ll just share the one E3 demo I imagined being shown, and only focus on Halo 4-5 characters. Never really done this before so I’ll try my best 
Much like many demos, this is probably early-mid game.
Trailer/cutscene plays, we see the UNSC Infinity either already in orbit or approaching a Halo, it could even be a throwback to when the Pillar of Autumn approaches Installation 04. Cut to Palmer, Lasky, and Roland on the Infinity bridge, same design as previous games.
Palmer- “Tom I can assure you Fireteam Majestic is more than capa-”
Lasky- “I’m well aware of their capabilities Sarah, but I have them on assignment already. Roland, show us what you’ve got.”
Roland-“Topographical scans haven’t given me much to work with Captain, seems this Ring isn’t willing to give up it’s secrets so easily, and these towers (map pings at least 3 Forerunner towers) are at least partly to blame.”
Lasky- “You think these towers are the reason we can’t find the Cartographer?”
Roland- “Unless I’ve gotten far worse at scanning than I realize… then yes, I can reasonably assume that these towers are stopping us from gathering any actual useful information.”
Palmer- “What I’m hearing is a ground operation, right?”
Roland- “Ground operations, Commander, you see because-”
Lasky- “We got it Roland, if we’re doing it the old fashioned way I know just the man for the job”
This is where it cuts to Chief, and at this point i either had the idea of you getting control of Chief here, and finding your way to the Bridge and being able to explore the Infinity (at least some portions of it), OR there would be some dialogue, the Chief enters the bridge and after being greeted and some dialogue about the operations it cuts a first person view.
From here you see a holographic display of the Halo ring, and for this point in the story (and demo) you only see a section of it. You can choose between multiple sections of the Ring to deploy to, similar to larger zones say in Borderlands or Destiny, so open-world, but only in a sense. These different zones have different biomes, the most common being Forest, similar to Installation 04, but like in the first Engine demo, there are some deserts and very mountainous areas, probably even snowy areas and lakes and oceans. For this demo you can see there are different places you could visit on the Ring but we are limited to the area with these towers.
For this part I thought maybe we could choose some sort of simple loadout (but wasn’t sure if weapon loadouts would fit well). But we see here we also have the ability to call in reinforcements, and we can choose what kinds we want, from calling in some Warthogs to a Scorpion, from some squads of Marines to a group of ODST’s. And possibly other abilities that are kept secret (for now).
After everything set and ready to go, a Pelican leaves the Infinity with the Chief and some backup on board.
Lasky- “We tried to find the best LZ we could Chief, but the Covenant might see us coming, so keep your eyes peeled, and stay safe down there, Lasky out.”
The Pelican lands and we’re given a stunning view of the Ring, landing higher up on a hill, not the same hill we saw in the Engine demo, but you can imagine the view. We look up and of course the Ring, similar to what players saw in Halo 1, we also see birds flying off in the distance and plenty of ambient noise, we see the clouds move along in the sky.
On the HUD we either see a box pop up similar to Halo 4 when characters spoke and we see their face (i kind of prefer this) or just voice box to let us know who’s talking.
Roland- “Alright Chief your targets are the 3 Forerunner towers located in this valley, marking them now for you” “Looks like the Covenant are already heading to this one (pings a tower), it’s farther away but could be worth taking them down before they fortify it.”
We now have the choice of 3 towers to choose from, all varying distances away, or we could just explore. As hinted at by Roland’s dialogue this Ring can change and evolve, if we go to the farthest tower now we can wipe out Covenant forces before they dig themselves in. This means gameplay can vary quite differently depending on how you approach the game. We go now, we might face a few ghosts, some enemies at longer range in an open area, even a dropship letting off troops. Or we head to an empty tower, maybe even find some weapons, then later that tower is fortified. Now there are turrets, closer quarters, maybe some other obstacles.
For this demo we go to the closest tower, within walking distance. Here we get to traverse a swath of trees, branches crunch under our armor and the sounds change depending on whether its dirt, gravel, or wet mud. Light shines through the trees but the cover is thick, so its still fairly dark, showing off RTX technology. We look to either side with Marines by our side, weaving in through trees, climbing over a fallen tree, showing off new dynamic animation (which we see more of later).
We progress, tower deactivated, its time to go to the farther tower and take out the Covies. We call in a Warthog or two (or they are delivered to us in some way, by Pelican of course)
That classic warthog engine revs up, a Marine jumps on the turret, the ammo jiggles from the movement. Tire tracks are left in the dirt when we drive.
We get to the tower, time to fight. Typical Halo battle here, we drive through with a Warthog, it tears through Covies. They try to run for cover, and hide behind shield emplacements or nearby trees, bullets ricochet off the shield, and splinter the wood off trees. After some fighting, the Warthog gets too damaged, time for the AR. We use that for a while, maybe pick up a plasma rifle, we chuck a frag grenade that leaves a noticeable crater in the dirt, its shockwaves shakes everything, we might even hear the dirt it sends into the air patter on our helmet.
Roland- “Picking up a faint signal… Oh… That Elite is calling for reinforcements Chief (nearby Elite is pinged in some way), unless you really like killing Covenant you may want to stop him!”
We fire some shots from our AR/Plasma Rifle, its too far away. We switch to the BR, its closest in design of course to Halo 3’s BR. Take some shots, Elite stumbles, we finish him off.
Roland- “Good job Spartan I think that did… the… uh oh, sending you some heavy firepower now.”
Lasky- “Roland i didn’t authorize… Uh, nevermind… Prioritize that order!”
“Hostiles inbound, or Reinforcements Incoming” is red on the HUD. We look into the sky and see the Infinity in orbit, and a Pelican coming in hot with a Scorpion tank and Hornet/Falcon/Wasp? escorts. It drops it, a loud clank/thud as it lands, as we enter it, ahead of us in a fairly clear area, a Scarab lands blasting away nearby trees and kicking up a massive cloud of dust. As it fires up its beam, the tank chambers a round, and the Aerial escorts fly overhead. End of demo. Nostalgic music plays.
If you took the time to read this thanks! I probably missed details but im out of words now D: