- We play as Spartan IIIs. Jorge is the only Spartan II on the team.
- Carter 259 and Kat 320 are the only members of their original squad.
- Jorge is a heavy weapons specialist.
- "Skully" now has a name, Emile 239. He's the silent type of the game.
- The sniper is called Jun 266. He's thoughtful and taciturn.
- We can customise the appearance of the Lone Wolf by a small degree. Awesome.
- The game is apparently darker than any of the other Halo games, even more so than ODST.
- Human Insurrectionists are possibly in the game
- Bungie have once again made the Covenant more dangerous and frightening, as they were in Halo 1.
- Covenant soldiers no longer speak English, they speak in their own languages.
- A new enemy like a Jackal has been introduced, named a "Skirmisher." They are deadly and cunning enemies that attack in packs, and flank secure positions.
- Graphics have been improved drastically, as proven by in-magazine comparisons.
- Elites are back, and are more ferocious than ever.
- Larger scale combat will be in Reach. Where only 20 AI at a time could be on screen in Halo 3, now over 40 AI and 20 vehicles can be present at a time.
- Scenes are more cinematic.
- Noble Team splits up at a point in the story.
- Health Bar is back along with energy shield.
- Single shot rifle like the Halo 2 E3 demo is in the game, named the Designated Marksman Rifle (DRM)
- Sniper, AR and Magnum make a return. Gun sounds are more realistic.
- Needler Rifle is in the game, a mid-range headshot capable weapon.
- Spike Grenades and Flame Grenades are out. Only frags and plasma remain.
- Helicopter Transport is called the Falcon.
- Civillian vehicles are now drivable.
- Fully stealthy gameplay is now possible.
- Assassinations are possible with a knife by holding down the melee button.
- Sprinting is now possible through an equipment like mechanic.