firstly i want to apologise for all the links and stuff, im thinking of making a video but for now this is all ive got, please tell me what you think and if you want me to analyse some more footage 
PHANTOM CRASH =
in the trailer actually it was game play from E3 we saw towards the end cortana screaming “I WILL NOT ALLOW YOU TO LEAVE THIS PLANET” now, if you look at one of the scenes here you will see the chief on a ghost, now this then gets enveloped in an explosion, at first i thought explosive, but on closer inspection i saw it was a phantom crashing into the hill side by him, if you slowly look through the frames then you can see how great it looks!
look around 5:18 in the vid below, if you pause it you can see the phantom!!!
ok so sorry for not making a video or anything, but if your interested then take alook at some of these i found.
NEW PELICAN TURRET =
ok if you look at this and go to 1:43 then you can see the new pelican turret
INFINITY SCALE =
ok so to give a sence of scale for the infinity, if you look here: and look very carefully at 0:16 then you can see under, and slightly to the right, the holo-deck (round thing at the top) you can see 3 small balls.
Now if you look here: at 1:17 oh look at that 117 lol, ok so if you look here then you will see the holo deck and the 3 balls, also there doesn’t seem to be windows here like there were in the last shot, maybe this is not complete by 343 or maybe infinity has blast doors which would make sense?
http://www.youtube.com/watch?v=n9fRP4KRL1I&feature=g-vrec
WARTHOG TURRET COOL DOWN =
just watched another thing, well i think the warthog turret may have cool down, like the one in reach, as when its firing you can hear a sorta squeaking noise, that gets higher the more you fire, thus i think once it reaches its peak go to 1:00
http://www.youtube.com/watch?v=JNDifQKdp6I&feature=relmfu
COVIE ALLIES? =
ok so i watching the halo 4 e3 game play… again and i started to think about just at the beginning when chief over looks the infinity, that the covies are not attacking, now we do see covies attack later, and it is confirmed that these are a splinter group from the main covies, most likely the servants of the abiding truth, so the banshees are not attacking the infinity (i am talking about the banshees far over head, already at the infinity, not the ones travelling over chiefs head), neither is the phantom, it could be they are occupied with the forerunner ball, what i think is a cryptum, but it looks to me as these maybe friendly, also these covies are not attacking chief, and if they were bad guys then i think they may want to kill him since he defeated their covenant, so why are they not attacking? maybe just distracted or actually allies?
starts at 1:10 here
http://www.youtube.com/watch?v=n9fRP4KRL1I&feature=g-vrec
Also we still have not seen anything that looks like the thing at the end of the concept art trailer…