well looks intresting but i think Halo has lost alot of it's intresting points.
Halo 1 had the best campain. Halo 2 had the best Multiplayer. Halo 3 had forge but i didn't like the story so much but the graphics where great. Halo 3 ODST was kinda ok but it was an expantion pack to get recon Halo: Reach Unknown.
It's harder to kill enemies in Reach compared to the other games in the series. Takes half a magazine of assault rifle rounds to kill a Grunt, but the good thing in campaign is that Brutes don't go berserk in the game.