It's almost like they saw the changes id made to Doom's combat with Eternal and decided that they should introduce a grappling hook and let Chief jump higher. The demo was clearly put together to highlight a more frenetic pacing and increased verticality. All they need is a double-dash evade now...
Combat certainly looked better than expected so no complaints there. I'm interested to see where they go with it.
The world looks good. They're obviously trying to tap into the first game's nostalgia and that's fine. I'd like to see weather effects and a more diverse biome. Give me steamy rainforests, wind battered stormy coastlines, muddybbogs and swamps etc. Granted the pop-in seen in the demo was jarring but that should be easy enough to fix.
My only real issue with it visually is that it looks too clean. It's almost clinically clean, particularly Chiefs armour and the weapons. I want to see grease stains, scuffs and scratches, some sort of wear on weapons. Right now the weapons don't even look at good as Reach's and very inferior to something like Destiny 2 and Metro Exodus.
I also have to assume that they'll build a battle royale mode. I can see that working well in the context of having it set on a Halo ring world and they already have a shitload of item pickups, vehicles etc. Need to see much more dense geometry for that though, super wide open spaces just leads to everybody playing as a sniper.
I'm not blown away and I suppose I'm pretty disappointed overall, but maybe it will work out. If the Covenant are the main enemy faction here I'll be happier than I was with 4 and 5.