Halo: Reach‘s re-release is a mostly pristine remake, with very few significant changes to discuss. One of the biggest besides the changes to customization progression, though, is one you may not have noticed, the location of the crosshair.
The crosshair is located right at the center of the screen. For most modern games (and older games for that matter), this is normal and was the norm for the Halo series from Halo 4 onward. However, in Halo 2, 3, and Reach, the crosshair was shifted down a bit, being a third of from the bottom of the screen.
The position serves a few purposes. It made “head glitching” harder, it increased vertical FoV in a roundabout sort of way, and it made the crosshair line up a bit more naturally with the heads of the incredibly tall Spartans and Elites.
If you played Halo: Reach a lot back in the day, you might find your aim is feeling a bit off, and the new crosshair placement could be why. Thankfully it’s easy enough to change.
Just go to Settings, Gameplay, and then toggle the “Crosshair Position” option at the top from “Centered” to “Classic” and see if it helps your aim out. You’ll be more likely to feel the change in the game modes like SWAT or Snipers, where headshots are vital.