Wow this thread needs to receieve a quick revive before the game is released. Hmm lets see where to start the recap of all the things missed. A breif summary will be mad with a link to more info about it below in the spoilers.
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New changes:[/h]
Flood is the new infected. As the change states, you play as flood infected spartan 4's with claws.
No longer a rank system like reach, but just a level up one like in rpgs.
No forge world this time, but three very awesome looking maps, one of which is a huge surpirser
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New stuff added:[/h]
A mech called the mantis and a new way to teabag, and to top it all off. A map remake reveal. The mantis will be part of the campaign too
Some old, new, and returning weapons of the three factions. yes that is right three. Covenant, Promeathen, and UNSC.
The elephant will not make a return, but will be replaced with a newer larger cousin the mammoth.
http://halo.wikia.com/wiki/Mammoth
Yes the covenant will make a return in halo 4.
No Firefight in halo 4, but has been replaced with a new mode called "spartan ops". which stated by 343 will be longer then halo 3 odst.
Armor abilities make a return too, some new, some old.
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Others:[/h]
Foward unto dawn just started recently. A 5 part live action webseries based on the captian of the UNSC infinity in his early days. An episoe will be released every friday for the next 4 weeks.
Halo 4 limited edition is 99.99+tax and will be in very limited quanties. Only a preorder will gurantee you a copy. Comes with a wargames pass for all dlc's, a 90 minute extended cut of forward unto dawn, and other bonus content.
http://halo.wikia.com/wiki/Halo_4_Limited_Edition
this is all that came to mind while doing this.