Halo 3 to 4 has s huge difference. You didn't get a chance to play halo reach? All the halo games are different, each add something new but reach and 4 added the most. Reach to 4 isn't as drastic as 3 to 4. Halo reach was a bungie game. It had lots of new stuff 3 didn't. Was still fun though even with some flaws.