Plays okay for a tech preview. I assume pre-beta so some things are expected. With that said here is what I noticed. I will say what's good at the end, but the focus is negative so things can be improved upon.
1: Running an i9 and RTX 2080 the FPS could be better for sure. At some point I had around 100FPS, but during Saturday, there was a 5 GB update and it could only get around 80.
2: There is an issue where it does not keep all my settings; had to setup my key bindings, FOV and sensitivities every time I took a break (exited the game, and then came back).
3: The AI can be ridiculous with laser aim. Also, they don't seem to know you're there because of radar, they turn in an instant when there is the possibility of line of sight between you and them. I came around a corner and they were walking away from me but instantly turned around. This is not the way.
4: Dead players' grenades look like they are going to explode so it causes some confusion.
5: When sprinting, the screen shake seems too jittery. It's smooth while normally walking and jumping. Moving the screen shake slider zero seemed to do nothing for this.
6: Zoom, and this is my opinion, is hardly useful to me. First, calling it zoom isn't necessary anymore. It's ADS. Every other shooter is ADS. Every other shooter also doesn't kick you out of aiming down sight when you get hit. It absolutely throws aim off, please let us stay ADS. Take away that weird blurry filter on the pistol's zoom The skewer's zoom is all sorts of awful; dark red and blurry with vignette black borders.
7: The time to kill seems way long compared to previous Halo games. Maybe it was just me. With all weapons but was noticeable with the gravity hammer. Seems to now take up to two swings to kill.
8: An extension of time to kill is the melee. I know there was a known bug with melee not registering but I can't imagine it happening that often. 3 times on a bot and most of the time they laser me before the 3rd.
9: More on time to kill. Where is the normal shotgun? The heatwave and bullfrog took too many shots.
10: Assigning things in the customization is weird. To have to select the color to bring up another box to click the checkbox isn't intuitive.
11: The inclusion of battle pass confuses me. Do you really need to follow suit with all the other free to play people? Fortnite, Warzone/COD, Apex Legends, Rocket League, Valorant, etc. I know you're doing Halo Infinite Multiplayer as Free to Play, but we have to buy battle pass to get good stuff to customize? Remember Halo 2 and 3? Still good customization and those things weren't behind a paywall. There were challenges and not much was added to the games after release. I don't remember anyone complaining that they couldn't pay for a glittery assault rifle with pink tracers or purple zebra camo helmet. Halo doesn't need it. We don't need it. You can let CoD keep that stuff because if it causes issue there (problems with certain effects causing your vision to be obscured way more than if the enemy was shooting at with a normal weapon), then it can cause issues in Halo. I don't know what battle pass has or what you have planned, but if it's along the same lines, then that's a problem.
I know that this is the longest rant, but it's a very sore spot for me. For some reason a portion of the gamer population feels that if it's a popular game and it has a bunch of cool collectibles, they want them! Not bad by itself, but some feel they don't want to do the work themselves, so let's just download a little aimbot or wall hack program to help me run through this. I'd rather pay extra for the multiplayer to not have a battle pass. But neither would be necessary based on past Halo experiences not needing that. I really hope that focus would not be on cosmetics after the game release, but more on map releases, and balancing.
The good: The game is simpler and paired down. And I love it. Less is more. This is actually hard to explain, but it's good to the point that I'm very excited. I can't wait to see improvements to how it plays on PC or if it can play the exact same with mouse and keyboard on both PC and Xbox, then I can play on my series x if my pc can't really handle it at release.
Edits after original post:
12: Trying to reassign push to talk crashed the game no matter what.
13: I like the marking system, but please let us mark after we die. On a team of randoms, most people don't care to look for dead players' skulls/x's. Marking would just be an extra nicety.
14: As I've been playing non bot matches now, the grenades are still an issue. Previous Halos have always been too grenade heavy and when you have each player able to start with 2 and pick up another set on the field, then it becomes a grenade throwing match more than shooter.